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KCSU17 Genetics > Exam 1 > Flashcards

Exam 1 Flashcards

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Biology 101 flashcards
1
Q

Genetics

A

branch of biology that deals with the heredity and variation of organisms

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2
Q

Human genetics

A

heredity and variation in humans

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3
Q

Medical genetics

A

subset of human genetic variation that is of significance in the practice of medicine and medical research

involves the application of genetics to medical practice

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4
Q

4 types of genetic diseases discussed in this class

A

1) Single gene disorders
2) Chromosomal disorders
3) Multifactorial disorders
4) Mitochondrial disorders

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5
Q

homologous chromosomes

A

posses genes for same characteristics at corresponding

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6
Q

gene locus

A

refers to specific location of gene on a chromosome

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7
Q

alleles

A

refers to different versions or forms of genes

represented by different DNA codes

humans have 2 copies of all their autosomal genes

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8
Q

homozygous

A

two identical alleles at gene loci

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9
Q

heterozygous

A

different alleles at the loci

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10
Q

genotype

A

individuals allelic constitution at locus

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11
Q

phenotype

A

observed characteristics of an individual, produced by interaction of genes with their environment

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12
Q

dominant

A

an allele that is expressed in the same way with a single copy as a double copy

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13
Q

recessive

A

allele that is pehonypically expressed as a homozygous (double copy) or hemizygous state

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14
Q

genome

A

totality of an organisms DNA

list of instructions encoded in DNA (needed to make a human)

made up of 3 billion bases of DNA split into 23 pairs

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15
Q

DNA sequencing

A

process of determining the exact order of bases (A,T, C, & G) in a piece of DNA

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16
Q

incomplete dominance

A

situation in which both alleles of a hertozygote influence the phenotype

typically somewhere intermediate between the two traits

ex. red and white make pink flowers

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17
Q

co dominance

A

situation in which a heterozygote shoes the phenotypic effects of both alleles fully and equally

ex. blood type

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18
Q

polygenic trait

A

an additive effect of two or more gene loci on a single phenotype character

ex. hair/eye color

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19
Q

4 laws of Heredity

A

Gregor Mendel

  1. law of uniformity
  2. law of segregation
  3. law of independent assortment
  4. Law of Dominance
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20
Q

punnet square

A

alternative method for determining genotypes in offspring

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21
Q

genetic code

A

combinations of mRNA codes that specify individual amino acids

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22
Q

codons

A

three nucleotide bases

coded by mRNA

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23
Q

wild type allele

A

DNA sequence of a gene that is associated with normal gene function

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24
Q

polymorphism

A

common differences in the DNA sequence

will have same function as wild type despite alteration of in gene sequence

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25
Q

types of polymorphisms

A

SNPs

tandem repeat polymorphisms (VNTRs and STRPs)

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26
Q

SNP

A

single nucleotide polymorphism

most ocommon type

variants at single nucleotide position on chromosome

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27
Q

tandem repeat polymorphisms

A

regions in the genome where the same DNA sequence is repeated over and over in tandem

include VNTRs and STRPs

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28
Q

reading assignment 1 (polymorphisms)

A

bc of large number of polymorphisms, each individual has their own DNA profile

can be ID by forensic science (PCR of sample DNA)

polymorphisms included in VNTR and STR

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29
Q

disease causing mutation

A

alterations in DNA sequence of gene associated with altered or absent gene function

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30
Q

double stranded helix

A

DNA

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31
Q

3 elements of DNA

A

phosphate
deoxyribose sugar
nitrogenous base

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32
Q

back bone of DNNA

A

phosphate and sugar groups that collect on outside

bases on inside

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33
Q

DNA bases

A

cytosine
adenine
thymine
guanine

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34
Q

Base paring

A

C –> G

A –> T

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35
Q

bonds that hold the base pairs together

A

hydrogen bonds

link nucleotides from one phosphate to the next

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36
Q

DNA coil levels

A

DNA coils around histone core =nucleosome

nucleosome coils = helical solenoid

solenoids coil into chromatin loops = chromosome

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37
Q

genes are arranged along ___

A

chromosomes

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38
Q

chromosomes

A

threadlike structures consisting of chromatin nd manuver DNA through cell division

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39
Q

how many pairs of chromosomes

A

23

22 pairs are autosomal and 1 set of sex chromosomes

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40
Q

diploid cells

A

somatic

contains two complete sets of chromosomes

consists of 23 homologous chromosome pairs, one set donated from ea. parent

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41
Q

mature diploid cells = how many chromosomes?

A

46 chromosomes (2n)

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42
Q

mature diploid cells = what division?

A

mitosis

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43
Q

haploid cells

A

sex cells

one copy of ea. chromosome (half the usual number)

typical state for gametes

after meiosis number of chromosomes in gametes is halved

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44
Q

mature haploid cell

how many chromosomes?

A

23 chromosomes (n)

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45
Q

mature haploid cell division?

A

meiosis

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46
Q

mitosis

A

part of the cell cycle by which chromosomes in the nucleus are separated into two identical sets of chromosomes each with its own nucleus

process of cell division for diploid cells

no crossing over

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47
Q

stages of mitosis

A 
interphase 
prophase
metaphase
anaphase
telophase
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48
Q

interphase

A

cell spends most of life here

DNA synthesis takes place

RNA and protein synthesis occurs

cell doubles in size

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49
Q

end of interphase:

A

cell has 2 ID copies of each of 46 chromosomes (92 total)

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50
Q

cells spend most of their life in which phase?

A

interphase

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51
Q

prophase

A

cell is full of chromatin and replicated

chromosomes are visible

sister chromatids are joined at the centromere

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52
Q

sister chromatids

A

two identical copies of chromosomes

joined at centromere during prophase

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53
Q

metaphase

A

chromosomes are most condensed now

EASIEST to visualize

centromeres line up at the equator thanks to spindle

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54
Q

anaphase

A

centromere of ea. chromosome splits

46 chromosomes are pulled to the side

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55
Q

telophase

A

nuclear membrane forms around ea. set of 46 chromosomes

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56
Q

result of mitosis

A

2 diploid daughter cells are created

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57
Q

meiosis

A

specialized division of sex cells

results in formation of egg and sperm

two sets of division

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58
Q

interphase I

A

replication of chromosomal DNA

cell suspends their time here

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59
Q

prophase I

A

homologous pairs of chromosomes become closely associated with their length via synapsis

forms tetrad

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60
Q

synapsis

A

joining of chromosomes

2 pairs of chromosomes v/2 chromatids ea.

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61
Q

metaphase I

A

2 pairs of chromosomes align on equatorial plane

forms the meiotic spindle

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62
Q

anaphase I

A

first division begin

two pairs of chromosomes are pulled to opposite ends of cells

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63
Q

telophase I

A

nuclear membrane reform and the cells complete division

equally in spermatogenesis (consisting of 2 chromatids)

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64
Q

results of meiotic division I

A

2 cells with 2 sister chromatids

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65
Q

interphase II

A

starts right after telophase I

no additional round of DNA synthesis

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66
Q

prophase II

A

chromatids join together at the centromere

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67
Q

metaphase II

A

chromosomes condense

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68
Q

anaphase II

A

chromosomes split at centromere

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69
Q

result of meiosis II

A

4 haploid cells

half the chromosome number

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70
Q

telophase II

A

differs in males and females

division of cytoplasm

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71
Q

spermatogenesis (telophase)

A

cytoplasm is divided equally among daughter cells

result: 4 equally functional haploid cells

continues throughout lifetime of males

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72
Q

oogenesis (telophase II)

A

unequal divisions of cytoplasm forming the egg cell and another polar body

result: 3 polar bodies with 1 functional ovum

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73
Q

different stages of oogenesis

A

primary oocytes are formed in utero, suspended in prophase I until puberty

onset of menses primary oocytes finish meiosis I during ovulation

meiosis II then proceeds after fertilization

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74
Q

how are chromosomes transmitted from parent to child?

A

replication of DNA (during fertilizations)

proteins coded by these genes are expressed via transcription and translation

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75
Q

gene

A

distinct sequence of DNA that codes for a particular protein

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76
Q

chiasms

A

points that chromatids attach

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77
Q

recombination

A

crossing over of chromatids at chasms

creates genetic variation

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78
Q

chromosomal crossover

A

exchange of genetic material between homologous chromosomes

prophase I of meiosis

occurs when regions of chromosomes break and attach to the other ones

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79
Q

genetic code

A

combinations of mRNA codons that specific individual amino acids

refers to how the nucleotide language of DNA gets translated and transcribed into amino acid language of proteins

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80
Q

DNA replication

A

DNA is copied during every division

DNA molecule unzips, exposing 2 parental stands and ea. strand serves as a template to develop the new strand

begins at multiple points with multiple separations

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81
Q

separation bubble

A

sites where the DNA strands separate

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82
Q

how does DNA direct protein synthesis?

A

through mRNA

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83
Q

gene expression

A

process by which the information encoded in a gene is used to direct the assembly of a protein

consists of transcription and translation

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84
Q

transcription

A

process of copying DNA into mRNA by enzyme RNA polymerase

occurs within the nucleus

DNA code is transcribed into a complementary mRNA molecule

SELECTIVE

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85
Q

mRNA

A

comprised of codons

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86
Q

mRNA processing

A

occurs before the primary mRNA molecules leaves the nucleus

excision of the introns from mRNA

then it leaves nucleus and enters cytoplasm to build proteins

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87
Q

translation

A

ribosomes bind mRNA/codons bind tRNA molecules

tRNA molecules add AA specific to the codon to build a polypeptide chain and give rise to a protein

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88
Q

what causes difference in DNA expression

A

different proteins expressed in different area of the body DNA can differentiate this

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89
Q

expressitivity

A

relative capacity of gene to affect the phenotype of organism

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90
Q

cofactors involved in DNA synthesis

A

RNA polymerase enzymes
promotor nucleotide sequences
enhancer/activators of silencer proteins

etc.
very complex and very regulated

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91
Q

source of genetic variation

A

mutation

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92
Q

advantages of mutations

A
  1. changes the DNA to get new forms of alleles
  2. would be no change w/o the
  3. mutations result in genetic variations

advantageous mutations are often passed onto next generation

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93
Q

disadvantage of mutations

A

may result in changes to cell function that causes death or disease

typically not preserved

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94
Q

gain of function mutation

A

good or bad

  1. results in gaining a new product
  2. can result in over expression of product
  3. can result in inappropriate expression of the product

often dominant disorders

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95
Q

loss of function mutation

A
  1. result in loss of product (recessive)
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96
Q

heterozygotes and loss of function

A

not effected by this unless there is a loss of more than 50% of product

otherwise the remaining alleles are still able to compensate

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97
Q

why do mutations occur

A

action of damaging chemicals or through errors in DNA replication processes

can change when DNA is undergoing replication

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98
Q

mutation causes

A

spontaneous

induced (radiation/chemcial)

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99
Q

spontaneous mutations

A

arise naturally during the process of DNA replication

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100
Q

induced mutations

A

caused by natural or human made agents

physical or chemical

alter structure or sequence of DNA

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101
Q

mutagens

A

agents that alter the DNA sequence

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102
Q

radiation mutagens

A

can be ionizing or non ionizing

103
Q

ionizing radiation

A

charged ions are ejected from an atom and produce free radicals that cause damage to cells/DNA/lipid membrane

104
Q

non ionizing radiation

A

NOT from charged ions

can move electrons from inner to outer orbits within an atom causes the atom to become chemically unstable

ex. UV radiant

105
Q

UV radiation

A

non ionizing

causes formation of covalent bonds b/t the bases (instead of H)

gives rise to pyrimidine dimers

unable to pair properly with purines during replication = base substitution

can’t reach germ line cells but causes skin CA

106
Q

chemical mutagens

A

can cause mutations in cells by altering DNAs structure:

forming base analogs, intercalating agent

107
Q

base analogs

A

chemical mutagens

DNA bases are substituted with another

108
Q

intercalating agents

A

chemical mutagens

physical insertion between existing bases

109
Q

mutation repair mechanisms

A

body is good at repairing itself

damage reversal
damage removal
damage tolerance

110
Q

damage reversal

A

simplest mechanisms

enzymatic action restores normal structure WO breaking the backbone

111
Q

damage removal

A

cutting out and replacing a damaged or inappropriate base or section of nucleotides

112
Q

damage tolerance

A

not true repair but way to cope with damage so life can go on

113
Q

how often does mutation occur?

at nucleotide level

A

10^-9 per base per cell division

114
Q

how often does mutation occur?

at gene level

A

variable

ranges from 10^-4 to 10^-7

115
Q

mutation rate varies with:

A
  1. size of gene (bigger gene is more likely to be mutated)
  2. some nucleotide sequences are more susceptible
  3. age of parent during reproduction
116
Q

cell type where can mutations occur?

A
  1. single germline cell
  2. exclusively somatic cells
  3. in some germline and some somatic cells
  4. in all cells
117
Q

where do most mutations occur?

A

somatic cells

most of our cells are diploid so more mutations here

ex. cancer, aging

118
Q

germline mutations

A

sex cells, mutation in sperm or ovum

the only mutations of genetic consequence that can be inherited

119
Q

reading assignment

radiation exposure

A

Hiroshima and Nagasaki survivors

compared exposure of radiation

those closer to blast = higher exposure

abnormalities between group were insignificant

most of the results were problems on somatic cells not germline cells

120
Q

mosaicism

A

refers to existence of two or more genetically different cell lines in an individual

mutation occurring in one cell of the embryo and all descendants of THAT cell have mutation

higher mosaicism = greater variability

121
Q

disorders that are associated with mosaicism

A

trisomy 21
turner syndrome
Klinefelter syndrome

122
Q

cause of alterations to genes or DNA sequences

A

alteration of single DNA base pair

alterations caused by gain or loos of entire chromosome

123
Q

mutations of single base pairs:

A

mutations that take place in the coding DNA or in regulatory sequences

can’t be seen on microscopy

124
Q

what happens if one of the bases is changed from C to A?

A

will have a significant impact on the amino acid

125
Q

consequences of single base pair mutation

A 
silent mutation 
non silent (nonsense or missense)
126
Q

silent mutation

A

a mutation that is tolerated in most cases

no consequences of this

127
Q

non silent mutation types

A

missense

nonsense

128
Q

mis sense mutation

A

changes the codon to one that will encode for a DIFFERENT AA

may change the protein enough to cause ti to be unstable or structurally abnormal

129
Q

nonsense mutation

A

changes the codon from encoding an AA to encoding a stop codon

130
Q

base pair deletion or insertion can result

A

in extra or missing amino acid or protein

this is particularly problematic if the extra pairs are not multiple of three

131
Q

frameshift mutation

A

when an insertion/deletion is NOT a multiple of 3

shifts the DNA base pairs

causes all the following AAs in sequence to be different, creating abnormal protein/none made at all

132
Q

in frame mutation

A

occurs when insertion/deletion IS multiple of 3

changes only a few Das

may have functional protein

133
Q

splice site mutaitons

A

alters the patterns of mRNA splicing

occurs at intron exon boundaries

134
Q

promotor mutation

A

alters regulation of transcription or translation

can result in net increased or decreased gene expression

(regulatory region mutation)

135
Q

Hemoglobin

A

found RBC carries oxygen from the lungs to the body tissues

2 alpha and 2 non alpha chains

136
Q

non alpha chains

A

gamma chains (fetus)

beta chains (adults)

137
Q

Hg F

A

2 alpha chains

2 gamma chains

138
Q

HgA

A

2 alpha chains
2 beta chains

form adult hemoglobin 18-24 weeks

139
Q

Hg A2

A

2 alpha chains

2 delta chains

140
Q

beta chains (genes)

A

encoded by one gene on chromosome 11

141
Q

alpha chains (genes)

A

encoded by 2 genes on chromosome 16

4 alpha global genes exist in ea. cell (each one responsible for 25% of HgB synthesis0

142
Q

genese and HgB control

A

2 beta global genes express their protein in a quantity that is EQUAL to the four alpha global genes

2/4 contribute equally to production of subunit

143
Q

hemoglobinopathies

A

single base mutations of human Hg

most common group of single gene dx

144
Q

3 groups of hereditary hemoglobin disorders

A
  1. structural variants
  2. thalassemia
  3. hereditary persistence of fetal Hg
145
Q

sickle cell anemia

gene mutation that causes it:

A

Single missense mutation of valine for glutamic acid at pos. 6 of beta globin chain

results in defective allele HgS

146
Q

sickle cell

Pathophysiology of defect

A
  • sickle cell crises – activity that boosts body’s requirement for O2 (illness, stress, altitude)
  • hypoxia can cause severe pain during crisis
  • chronic and progressive destruction in organs and tissues thru body due to infarctions
  • molecules stick together and form long polymer chains which distort the cell and cause it to bend out of shape (tangled in vessles = infarctions)
  • cells are destroyed (hemolysis) to get anemia
147
Q

sickle cell inheritance patterns

A

Autosomal recessive

1 in 400 AA births

Presents in childhood damages to spleen most

148
Q

sickle cell anemia advantage

A

-individuals with AS genotype have sickle cell trait phenotype; mis-shape and deflated RBCs, rarely develop severe anemic symptoms

  • Advantage: sickle cell trait and dz have resistance to malaria b/c of deflated RBCs
  • Disadvantage: sickle cell dx is deadly, SS genotype kills during childhood. Sickled cells are destroyed = anemia
149
Q

hand foot and mouth syndrome

A

usually 1st symptom of sickle cell

Caused by clogging/infarcts, treat with pain meds and fluid

150
Q

sickle cell patients are susceptible to…

A

Very susceptible to infection bc spleen is damaged

treat w/vaccines against penumo bacteria, prophylactic penicillin and hydroxyurea to increase HgbF

151
Q

acute chest syndrome

A

sickle cell

occurs when lungs are deprived of O2 during crisis

152
Q

treatment of sickle cell

A

Blood transfusions (reduce pain crises)

need chelation therapy to lower Fe levels

153
Q

alpha thalassemia

gene mutation that causes it:

A

deletions of 1+ alpha globin genes on C16

results in reduced synthesis or stability of alpha chain; alpha globin gene fails

Trait 1-2 genes, Dx= 3-4 genes

154
Q

alpha thalassemia pathophysiology (7)

A
  • Decreased synthesis of one+ globin chains = imbalance in amounts of alpha chains.

Result is decreased O2 binding capacity, producing hypoxemia

  • results in microcytic, hypochromic anemia
  • imbalance in the ratio of alpha to beta chains (shortage of alpha and excess of beta)
  • homotetramers form from excess B-chain
  • affects both fetal and adult, bc BOTH fetal and adult Hg contain alpha chains
  • severity of dx is dependent on number of alpha globin genes affected
155
Q

thalassemia (alpha and beta) inheritance pattern

A

Autosomal recessive; occurs esp. among people in SE Asia and Mediterranean Basin

156
Q

thalassemia advantage (alpha and beta)

A

those with thalassemia trait confer resistance to malaria

157
Q

symptoms of alpha thalassemia

A
  • Trait = not severe symptoms

- Disease = symptomatic, severe anemia and splenomegaly (3-4 genes)

158
Q

HgbH Dx

A

3 dz genes
only one functional alpha globin gene

severe and transfusion dependent

lots of hemolysis

alpha thalassemia

159
Q

Hydrops Fetalis

A

4 dz genes

typically dies as a fetus

incompatible with life

seen mostly in SE Asia

160
Q

genetic cause Beta thalassemia

A

Single base pair substitutions in one or more B-globin gene at C11

results in reduced synthesis or stability of beta chain

beta globin gene fails

161
Q

B-thalassemia pathophys (5)

A
  • imbalance in amounts of beta chains
  • microcytic hypochromic anemia
  • imbalance in ratio of alpha to beta chains (shortage of beta subunits and an excess of alpha subunits)
  • Homotetramers form from the excess alpha chains
  • both globin genes are present in cell, but fail to produce HgB adequately
162
Q

treatment B-thalassemia

A

correction of anemia by blood transfusion, control of iron accumulation via chelation, bone marrow transplant

163
Q

minor B-thalassemia

A

trait

little to no symptoms, only if one beta gene fails

Diagnosed with HgB electrophoresis

164
Q

major b-thalassemia

A

disease

occurs when both B-genes fail

produces severe anemia (Cooley’s Anemia)

165
Q

Hereditary persistence of Fetal Hemoglobin

A

when the adult HgB fails to switch from gamma to beta

2 a and 2 g HgB

non treatable, typically benign

166
Q

Hereditary persistence of Fetal Hemoglobin

pathophysiolgy

A

Impaired switching of globin synthesis

Defect in HgB switch mechanism

167
Q

chromosomal mutation detection methods

A

FISH

karotyping

168
Q

karyotyping

A

groups chromosomes based on relative sizes and legnths of 2 arms (p and q)

can count # of chromosomes and look for structural change to ID cause

cell is fixed with chemical and stained to reveal characteristic patterns

169
Q

FISH

A

detects DNA sequence deletions of excess chromosome material using fluorescent labeled DNA segment

shows detection of tirsomy 21

170
Q

cytogenetics

A

study of chromosomes and their abnormalities

171
Q

centromere

A

where two chromatids are linked

172
Q

p-arm

A

short arm of the chromosome

173
Q

q-arm

A

long arm of the chromosome

174
Q

telomeres

A

ends of the chromosomes

175
Q

metacentric

A

when centromere occurs near middle of chromosome

176
Q

submetacentric

A

centromere occurs b/t middle and tip of chromosome

177
Q

acrocenteric

A

centromere occurs near tip of chromosome

178
Q

chemical landing

A

ea. chromosome is numbered y bands from centromere out

179
Q

band 9q34.1

A

1st sub band of 4th sub band of 3rd subdued of long arm of chromosome 9

read backwards

180
Q

chromosome abnormalities are due to

A

abnormal number (loss of genetic material)

abnormal structure (relocation of genetic material)

181
Q

euploid

A

normal set of chromosomes

182
Q

polyploidy

A

extra set of the ENTIRE GENOME

not compatible with life, rare

183
Q

aneuploidy

A

number of chromosomes is NOT a multiple of normal haploid number

most common type

184
Q

MC cause of anyploidy

A

nondisjunction

185
Q

nondisjunction

A

occurs commonly in older individuals

chromosomes are defective in pulling apart

can occur during meiosis I or meiosis II

186
Q

nondisjunction in meiosis I

A

both homologous pairs go to same daughter cell, other gets none

187
Q

nondisjunction in meiosis II

A

can result in monsomy or trisomy

2 normal haploids, 1 cell with 3 chromosomes and one cell with 1

188
Q

autosomal aneuploidy

A

occurs to an autosomal cell

includes trisomy 21

189
Q

monsomy

A

missing once chromosome pair

*45 total chromosomes

most incompatible

190
Q

trisomy

A

one chromosome set consists of 3 copies instead of 2

47 total chromosomes

191
Q

chromosomal structural mutations

A

deletions
inversons
duplications
translocations

192
Q

deletions

A

loss of entire chromosomal segment and genetic material

193
Q

disease caused by chromosomal deletions

A

Cri-du-chat
Wolf-hirschhorn syndrome
WAGR syndrome

194
Q

Cri-du-chat

A

cry of the cat

characterized by high pitch cry

deletion on p of chromosome 5 (short arm)

195
Q

Wolf hirschhorn syndrome

A

micro deletion of telemetric segment of 4p

classic greek warrior helmet face

196
Q

WAGR syndrome

A

microdeletion of varying lengths along short arm of chromosome 11 (11p)

Wilms tumor, Anirida, Genitourinary abnormalities, Retardation

197
Q

inversions

A

extra copy of chromosomal segment caused by break and reverse sequence (normal phenotype)

198
Q

duplicaitons

A

less severe

chromosome segment is repeated producing extra alleles for a trait

ex. Pallister Killian Syndrome

199
Q

Pallister Killian Syndrome

A

duplication

extra chromosome 12 material

usually mosaicism

severe mental retardation, polydactyly

200
Q

translocation

A

exchange of chromosomal segments b/t two non homologous chromosomes

can run in family

two major types: robertsonian and reciprocal

201
Q

Robertsonian translocation

A

short arms of two NON HOMOLOGUS acrocentirc chromosomes are lost

LONG ARMS fuse at centromere to form SINGLE chromosome

causes monosomy or trisomy

202
Q

reciprocal translocation

A

occurs when breaks happen at 2 different chromosomes and genetic material is exchanged

carrier is unaffected but offspring had partial trisomy

Derivative chromosomes

203
Q

trisomy 21

A

most common aneuploidy

90% nondisjunction occurs during meiosis I in oocyte

great survival rate into adulthood, 10% past 50

204
Q

characteristics of trisomy 21

A 
simian crease 
heart defects 
most men are sterile
moderate to severe mental retardation (mosaicism) 
large tounge
205
Q

trisomy 21 cause

A

extra chromosome in autosomal cells during meiosis

maternal age is only known correlating factor

206
Q

edwards syndrome

A

trisomy 18

rare, most die in utero

unusually clenched fist

traced to nondisjxn in meiosis II of oocyte

207
Q

Patau syndrome

A

trisomy 13

very rare, 1/2 die in first MOL

characterized by oral facial clefts and polydactyly

208
Q

types of autosomal aneuploidy diseases

trisomy

A

downs syndrome/trisomy 21
edwards syndrome/trisomy 18
patau syndrome/trisomy 13

209
Q

tuner syndrome

A

FEMALE always (45,X)

missing X chromosome

210
Q

turner syndrome

characterized by

A

short stature

webbed neck

211
Q

turner syndrome treatment

A

GH and estrogen to promote sexual development

212
Q

Klinefelter syndrome

A

MALE (47, XXY)

characterized by taller than avg, low test score, *gynecomastia, reduced muscle mass

treatment: testosterone therapy

213
Q

summarizes total number of chromosomes, types of sex chromosomes and types of aberration present

A

chromosomal shorthand

214
Q

chromosomal shorthand

Normal Male

A

46, XY

215
Q

chromosomal shorthand

normal female

A

46, XX

216
Q

chromosomal shorthand

trisomy 21

A

47, XX+21 Female

217
Q

chromosomal shorthand

edwards syndrome

A

trisomy 18

47, XX+18 OR 47, XY+18

218
Q

chromosomal shorthand

turner syndrome

A

45, X

219
Q

chromosomal shorthand

klinfelter syndrome

A

47, XXY

220
Q

what may a family history show?

A

disorder is hereditary

clarify pattern of inheritance

enable you to determine risk of other family members developing condition

221
Q

red flags in a family history

A
  1. unusual physical findings
  2. congenital or early onset deafness/blindness
  3. rare cancers/tumors
222
Q

what questions must you ask when taking a family history

A
  1. sex of family member
  2. infection status
  3. relationship to other individuals
  4. biological relationship
223
Q

first degree relative

A

related at parent offspring level or sibling

50%

224
Q

second degree relative

A

removed by one addiotnal generation (grandparents, aunt/uncle)

25%

225
Q

third degree relative

A

first cousin, great grandchildren (12.5%)

226
Q

shorthand system of recording pertinent information about a family

A

genetic pedigree

starts with index case

227
Q

index case

A

AKA proprand or propsita

individual present with you/you are evaluating

indicated with a P and arrow pointing to shaded circle

228
Q

study the pictures of symbols on pedigree

A

:)

229
Q

characteristics of Mendelian traits

A

single gene affected
clear pattern of inheritance
complete penetrance

230
Q

5 pedigree patterns

A
  1. autosomal dominant
  2. autosomal recessive
  3. X linked recessive
  4. X linked dominant
  5. Y linked
231
Q

autosomal dominant

A

vertical pattern

every generation has dz

features:

  1. both sexes
  2. at least on affected parent
  3. child of affected and unaffected =50% chance
232
Q

autosomal recessive

A

horizontal pattern

parents are not symptomatic

features:

  1. both sexes
  2. 25% risk
  3. only one affected in one generation
233
Q

X linked recessive

A

exclusively MEN

if mother is carrier they have 50% risk of dz

no male to male transmission

234
Q

X-linked dominant

A

more female then male

all daughters of affected males are affected but no sones

235
Q

Y linked

A

only males

always have affected fathers

236
Q

penetrance

A

percentage of individuals having a genotype and expressing the phenotype

can be complete (always shows) or incomplete (do not show)

237
Q

degree to which a phenotypic characteristic is exhibited

A

expression

can vary depending on factors

238
Q

genomic imprinting

A

differential activation of genes

depending on which parent they are inherited from

239
Q

uniparental disomy

A

condition in which persons inherit 2 copies of chromosome form 2 parent and no form other

ex. c15

240
Q

example diseases of genomic imprinting

A

Prader Willi syndrome

Angelman syndrome

241
Q

Prader Willi and ANgelman syndrome

A

both caused by deletion of 3-4 mil BP from 15q

depends on if this deletion is in mom or dad

242
Q

Prader Willi syndrome

A

deletion is inherited from father

missing gene is active only on paternal C15 which encodes for RIBOPROTEINS

short stature and severe obesity result when this is deleted

most common GENETIC cause

243
Q

Angelman syndrome

A

deletion inherited from mother

missing gene only active on maternal C15 which encodes for protein involved with protein deflation

secrete mental retardation (typically happy)

treated with ritalin

244
Q

DNA mutation detection methods

A

protein electrophoresis
DNA amplification
microarray

245
Q

protein electrophoresis

A

DNA segments are loaded into gel and electric current is applied

separates proteins based on size (small go further)

reveals DNA profile by evaluating polymorphisms

246
Q

DNA amplification

A

PCR

duplicates genetic material at very fat rate
used to ID genetic fingerprints and detecting infectious dz

247
Q

mircorarray

A

sophisticated way to isolate abnormalities

looks for activation of genes within cell using a chip

determine genes that turn on in response to treatment or infection

248
Q

linkage analysis

A

diagnosed mapped genetic diseases

genes located along same region are transmitted together so you look for MARKERS on other genes

INDIRECT method

once linkage is established it can determine at risk individuals

249
Q

markers

A

used in linkage analysis to find problems diseases

often short tandem repeat sequences

250
Q

linkage analysis advantage

A

indirect diagnoses of at risk individuals

251
Q

linkage analysis disadvantage

A

must test multiple family members

recombination can mess with results

252
Q

direct mutation analysis

A

direct way to test if disease gene is known

diagnosis is made through direct ID of gene

253
Q

direct mutation analysis advantage

A

no family information needed and no risk of error from recombination

254
Q

direct mutation analysis disadvantage

A

must know which disease to look for

KCSU17 Genetics (14 decks)

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