Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

My M2M > Genetics unit 2 > Flashcards

Genetics unit 2 Flashcards

1
Q

pedigree

A

ancestry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Gene

A

a name given to some stretches of deoxyribonucleic acids (DNA) and ribonucleic acids (RNA) that code for a polypeptide or for an RNA chain that has a function in the organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

allele

A

a version of a gene. Allele’s are different forms of the same gene/genetic locus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Mendel’s Law of segregation

A

The Law of Segregation states that every individual possesses a pair of alleles (assuming diploidy) for any particular trait and that each parent passes a randomly selected copy (allele) of only one of these to its offspring.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

gamete

A

cell that fuses with another during fertilization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Mendel’s Law of Independent Assortment

A

separate genes for separate traits are passed independently of one another from parents to offspring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Genotype

A

A particular DNA sequence (allele’s at a locus). Refers to homologous alleles

-can be homozygous, heterozygous, or hemizygous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Phenotype

A

Observed/measured/expressed trait

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Hemizygous

A

Having only one chromosome in a diploid cell.

ex; In males (XY) that have just one copy of the genes on X chromosome or just one copy of the genes on the Y chromosome.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Penetrance

A

On/Off (if you have mutation are you affected/not)
Can have complete/incomplete penetrance

If have genotype but no phenotypical expression -> incomplete penetrance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

expressivity

A

severety of onset
age of onset

“like a dimmer control on a light”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Pleiotropy

A

complexity of gene (one organ or many)… “One Gene contributes to multiple phenotypic effects”

polysystemic -> systemic affects multiple
monosystemic -> affects only 1 system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Chediak-Higashi Syndrome

A
  • Autosomal recessive:
  • chromosome 1

lysosomal trafficking defect

Pleiotropy: light hair, albinism pigmentation, neuropathy, parkinsonism

  • Variable expressivity
  • Penetrance: In white cells of most, not all pts.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Semi-Dominant/ incomplete dominance

A

When the heterozygous phenotype is intermediate between the two homozygous phenotypes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Karyotyping and karyotype

A

Process of staining chromosomes in metaphase.

-stained, ordered, numbered BY- morphology, size, arm-length ratio, banding pattern

  • > diagnostic for some diseases (sex chromosome and trisomies)
  • > can be performed on many different tissues

A karyotype (Greek karyon = kernel, seed or nucleus) is the number and appearance of chromosomes in the nucleus of a eukaryotic cell. The term is also used for the complete set of chromosomes in a species, or an individual organism.

ex: the display of 23 paired and stained chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Non-allelic homologous recombination (NAHR)

A

Aberrent recombination because of misalignment of homologs at repetitive DNA sequences -> deletion and duplication.

This is during Meiosis (obviously since we’re talking about recombination). There are still seperate chromosomes, they now have slightly more or less DNA. This also can happen in DNA repair

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

“Tandem repeats/ satellite DNA”

A

Just means that there are independent sections of repeating sequences.

  • used in cytogenic banding
  • Specifict Pentanucleotide sequence 1, 9, 16, Y (hotspots for human specific evolutionary changes) found in heterochromatic regions
  • “Alpha-Satelite” (171bp repeat unit) found near centromeric region. Speculated to be involved in mitosis/meiosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

cytogenic banding

A

used to make karyotype stains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Dispersed repetitive DNA elements

A

These families can move around genome
-Alu Family = (SINE’s)- short interspersed repetitive elements about 300 bp, with 500,000 copies in genome.
-L1 Family = (Lines)-> long interspersed repetitive elements about 6kb length with 100,000 copies
-L1 & Alu speculated to have medical relevance
-Retrotransposition may cause insertional inactivation of genes
RNA->cDNA -> inserts itself

-Repeats may facilitate aberrant recombination
events between different copies of dispersed repeats leading to diseases…
- Non-allelic homologous recombination (NAHR)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

CNV (copy number variation)

A
  • A variation in number of copies of a certain section of DNA.
  • SIZE: 200 bp – 2 Mb
  • measured by array comparitive genomic hybridization (array cpg)
  • primary type of structural variation

For example, the chromosome that normally has sections in order as A-B-C-D might instead have sections A-B-C-C-D (a duplication of “C”) or A-B-D (a deletion of “C”).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

DUF1220

A

DUF1220 domains are approximately 65 amino acids in length and are located primarily on chromosome 1 in region 1q21.

DUF1220 is a protein domain of unknown function that shows a striking human lineage-specific (HLS) increase in copy number and may be important to human brain evolution. ->CNV’s

dosage may affect brain size (number of the copies)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

1q21.1 duplication

A

Macrocephaly and autism

DUF1220 area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

1q21.1 deletion

A

Microcephaly and schizophrenia

DUF1220 area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

autism and schizophrenia correlation

A

proposed diametric opposites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What portion of Human Genome is transcribed (through all of life)

A

1.5% WHHHHAAAT!!!???!?!?!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

chiasma (singular)

chiasmata (plural)

A

section of chromosome crossover in meiosis I
2-3 chiasmata per pair homologous chromosomes
->usually one on each side of centromere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

homologues

A

2 autosomal chromosomes that have the same genes (with possibly/definitely slight differences)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

sex chromosome crossover MALE

A

Cross-overs also occur within pseudoautosomal regions of sex chromosomes during male meiosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Meiosis I nondisjunction (%abnormal gametes?)

A

100%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Meiosis II nondisjunction (% abnormal)

A

50% (because it’s just one cell -> 2), the other cell -> II is normal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

G-banding or Giemsa banding

used in karyotyping

A 
GC does not stain well (grey)
AT does (black)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

chromosome classification by centromere (constriction) position

A 
Metacentric = centromere in middle
Submetacentric = closer to one end
Acrocentric = #5 in humans (13, 14, 15, 21 and 22), 1 side is repetitive satellite elements + a stalk of repetitive (hundreds of copies of ribosomal DNA in heterochromatic region). 14 is most common chromosome involved in robertsonian translocation.

See pg.62 T&T for satellite/stalk explanation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Aneuploidy

A

Loss or gain of certain chromosome
ex; trisomy 21, monosomy X
also 13 and 18

monosomy die in all but monosomy X

Most common mechanism: meiotic chromosomal nondisjunction (in meiosis 1)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

polyploidy

A

gain or loss of ALL chromosomes
i.e. triploidy (3N), tetraploidy (4N)
Not found very often (and usually fatal)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

terminalization and aneuploidy

A

Loss of cohesin (as you age?) allows chiasmata (site of recombination) to move to “termanalize” move toward end of homologous pairs, then they seperate = precocious seperation = meiosis I nondisjunction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

zygote

A

is the initial cell formed when two gamete cells are joined by means of sexual reproduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

epigenetics

A

the study of heritable changes in gene activity which are not caused by changes in the DNA sequence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Oncogene

A

A gene that has the potential to cause cancer. In tumor cells, they are often mutated or expressed at high levels.

39
Q

Allelic Heterogeneity

A

Different mutations in the same gene cause similar phenotype

Different mutations same gene = similar phenotypes

Different mutations at the same locus causes a similar phenotype. For example, β-thalassemia may be caused by several different mutations in the β-globin gene.

40
Q

Phenotypic Heterogeneity

A

Different mutations in the same gene/locus cause different phenotypes.

Different mutations same gene = different phenotypes

41
Q

heterogeneity

A

quality of being diverse and not comparable in kind

42
Q

Locus/genetic heterogeneity

A

A mutation in more than one locus causing the same/similar clinical condition

Classic example: Early onset Alzheimer disease (AD)

-> Mutations in 3 different genes all result in identical clinical presentation of early-onset AD

43
Q

Uniparental disomy

A

Heterodisomy: Meiosis I error -> usually benign (one allele from parental/maternal genes)
Isodisomy: Meiosis II error -> bc both are same parent -> could be recessive expression

44
Q

Balanced Structural rearrangement

A

Inversion, reciprocal translocation, and Robertsonian translocation

45
Q

Unbalanced Structural rearrangement

A

Deletion, Duplication, Ring Chromosome (arms have joined), Isochromosome (arms have duplicated)

46
Q

Epigenetics

A

Definition: mitotically and meiotically heritable variations in gene expression that are not caused by changes in DNA sequence

example: IMPRINTING!!!

47
Q

Imprinting

A

Reversible, post-translational modifications of histones and DNA methylation (CpG) are examples of epigenetic mechanisms that alter chromatin structure, thereby affecting gene expression.

48
Q

Imprinting Methylation

A

by MeCP (methyl CpG binding protein)

-> binds methylated CpG’s -> In complex with SWI/SNF and HDAC’s and HMT (histone methyl transferase)

compacts chromatin-»» silencing gene

49
Q

SWI/SNF

A

possess a DNA-stimulated ATPase activity and can destabilise histone-DNA interactions in reconstituted nucleosomes in an ATP-dependent manner, though the exact nature of this structural change is unknown.

–> affect chromatin remodling by moving histones around

50
Q

Imprinting distribution

A

Imprinted genes are usually clustered and account for about 1% of gene’s in genome

51
Q

_____ enzyme recognizes hemimethylated DNA in Mitosis

A

maintenance methyltransferase

52
Q

Chromosomal MicroArray (CMA)

A

1:Many 60 nucleotide sequences fixed.
2. DNA to study is added.
3. Gain/Loss/normal ration seen
Green = gain. Red = Loss. Yellow =normal ratio

Cannot detect SNP’s or balanced rearrangements. Poor at detecting mosaicism (15%).

Same sex DNA as control
You add c DNA fragments from across the whole HUMAN GENOME.

JUST DETECTS GAINS/LOSSES

53
Q

Methylation of DNA ONLY occurs at what sequence

A

on Cytosine of CpG

Does not affect base paring of 5-meC with G.

Contributes to gene silencing by solidifying the repressed state

54
Q

Hardy-Weinberg assumes

A

Random Mating of Large population
No selection
No Mutation
No Migration/Drift

55
Q

multifactorial inheritance + disease examples

A

Genetics + environment = disease

Some cancers				- Schizophrenia
Type 1 diabetes				- Cleft lip/palate
Type 2 diabetes				- Hypertension
Alzheimer disease				- Rheumatoid arthritis
Inflammatory bowel disease			- Asthma
56
Q

Phenocopy

A

Environmentally caused phenotype that mimics the genetic version of the trait.
-Environment MOSTLY responsible

  • ex: Thalidomide-induced limb malformation vs. genetically-induced.
  • ex: DM II (healthy person w/DM II vs overweight/poor habits person)
57
Q

Odds Ratio (OR) =

A

Risk of disease having a given gene variant /

Risk of disease not having a given gene variant

58
Q

Linkage disequilibrium:

A

non-random association of genes at two or more loci, that descend from single, ancestral chromosomes… It means that different genes aare inherited together more often than can be expected by chance.

59
Q

Microsatellites

also known as Simple Sequence Repeats (SSRs) or Short Tandem Repeats (STRs)
or
STRPs (Short Tandem Repeat Polymorphisms)

A

repeating sequences of 2-6 base pairs of DNA.[1] It is a type of (VNTR). They are used as molecular markers in genetics, for kinship, population and other studies. They can also be used for studies of gene duplication or deletion, marker assisted selection, and fingerprinting.

60
Q

DNA Human Variation

A

Minisatellites, Microsatellites, SNP’s, CNV’s.

Others: chromosomal or larger scale variations, rearrangements, translocations, etc

Variations can be silent (majority) or have a functional effect.

61
Q

Gene family

A

Gene family is composed of genes with high sequence similarity (e.g. >85-90%) that may carry out similar but distinct functions

Gene families arise through gene duplication, a major mechanism underlying evolutionary change

62
Q

Minisatellites

A

tandemly repeated 10-100 bp blocks of DNA VNTR (variable number of tandem repeats)

63
Q

Barr body

A

Heterochromatic mass present for inactive X chromosomes. (only 1 per inactive X)

64
Q

XIST gene

A

transcriptionally active on INACTIVATED X chromosomes, necessary for inactivation.
Produces non-coding RNA that associates closely with Barr body (initiates modification -> methylation and histone modification).

Side note: 10-15% inactive X chromosome is still expressed.

65
Q

SRY gene

A

It’s presence (on short arm of Y chromosome) leads to development of testes.

SRY (sex reversal Y) codes a TF binding protein (family of HMG (high mobility group) box family which binds to DNA, inducing differentiation of cells derived from the genital ridges into testes. (It opens the DNA to transcription)

In the absence of SRY, undifferentiated gonadal tissue -> Ovaries.

66
Q

WT gene

A

directs differentiation of the mesonephros (middle temporary kidney) and genital ridge, events that precede gonadal development. ( helps differentiate cells into undifferentiated gonads)

BUT

If gene mutated -> development of ovaries/gonadal dysgenesis despite Y chromosome presence.

67
Q

Sertoli cells

A 
NON-GERM cells within testes.
produce peptide hormone (all of these are the same, just different names):
Mullerian Inhibitory Factor (MIF) 
Antimullerian Hormone (AMH) 
 Mullerian Inhibitory Substance (MIS)

MIF prevents formation of mullerian duct derivatives (fallopian tubes, uterus, cervix, and upper portions of the vagina). Mullerian duct also called paramesonephric duct.

see slide 22

68
Q

Leydig cells

A

NON-GERM cells within testes-
produce testosterone in response to stimulation by the pituitary.

Testosterone promotes -> Development of Wolffian (mesonephric) duct into the epididymal duct and ductus deferens. And other secondary male characteristics. such as descent of testes

69
Q

Sex reversal

A

Gonadal sex is opposite of what is predicted from karyotype (genetic sex).

Mutations on Loci on chromosomes 9 (SF1),11(WT) and 17(SOX9), (and X really DAX1)) can lead to sex reversal (development of female gonadal/genital sex) in the presence of SRY expression.

examples:

MALE: SRY gene translocated onto an autosome in XX genotype.

FEMALE: Deletion of SRY gene (or) duplication of DAX1 gene

70
Q

Intersex (True hermaphrodite)

A

Both ovarian and testicular tissue are present. Clinical cases are generally found to be mosaic for expression of genes involved in
determination of gonadal sex. XX, XY chromosomal mosaicism is most common.

71
Q

Intersex (Pseudohermaphroditism)

A

Abnormal development of genital sex. External phenotype and, often, sex assignment at birth is at odds with genetic and gonadal sex.

Example: 1.female exposed to androgen in utero.
2. Male insensitivity to testosterone

72
Q

DAX 1

A

gene needed for development of ovary. DAX 1 (2x X chromosomes) is needed for “perfect” development of ovaries.

(ovarian development is primarily a default setting)

If there is a duplication of DAX1 gene in XY individual -> ovarian development despite presence of SRY gene

73
Q

Brain sexuality?

A

Nyep -> Dimorphic

74
Q

Compound heterozygote

Also called “genetic compounds”

A

2 different mutant alleles
vs
simple heterozygous (1 wild type and 1 mutant allele)

75
Q

Microcytosis

A

a condition in which red blood cells are unusually small as measured by their mean corpuscular volume

->microcytic anemia

MCV normal = 75-95fl
(deficiency = often iron or thalassemia problem)

76
Q

hypochromia

A

anemic condition due to a deficiency of hemoglobin in the red blood cells. with insufficient color or pigmentation

77
Q

Hemoglobin A2 components

A

Alpha2Delta2 = 4x tetramer (low in adult)**

vs

HbA = Alpha2Beta2 = 4x tetramer (high in adult)**

** given no hemoglobinopathies

78
Q

alpha-alpha vs alpha-beta interaction

A 
alpha-alpha = weak
alpha-beta = strong interaction
79
Q

Parental transmission bias

A

Trinucleotide expansion more prone to occur in gametogenesis of the male or the female

80
Q

Pharmacokinetics:

A

the rate at which the body absorbs, transports, metabolizes, or excretes drugs or
their metabolites.

concerned with whether or how much drug reaches the
target(s)

81
Q

Pharmacodynamics:

A

the response of the drug binding to its targets and downstream targets, such as
receptors, enzymes, or metabolic pathways

concerned with what happens when the drug successfully reaches its target

82
Q

Phase I vs Phase II pharmacokinetics

A 
Phase I (simplified): attach a polar group onto the compound to make it more soluble; usually
a hydroxylation step

• Phase II (simplified): attach a sugar/acetyl group to detoxify the drug and make it easier to
excrete

83
Q

cytochrome P450 (CYP450)

A

genes encode important enzymes that are very active in the liver and to a lesser extent in the epithelium of the small intestine.

->CYP450 enzymes metabolize a wide number of drugs.

->CYP families are involved in the Phase I
metabolism of ~90% of all commonly used
medications.

CYP3A4 itself takes part in the metabolism of
over 40% of all drugs used in clinical medicine

CYP family USUALLY inactivates drugs, but SOMETIMES activates them

ex CYP2D6 codeine -> morphine
clearance by CYP3

84
Q

1 glass Grapefruit juice inhibits _____

A

CYP3A for 24-48hrs (intestinal inhibition)

So if taking Felodipine (antiHTN) with grapefruit juice-> CYP3A inhibition -> less clearance Felodipine -> increased drug in system -> hypotension

85
Q

Renal transplant develops fungal infection

A

Reduce cyclosporin (an immunosuppressant) because ketocoazole (antifungal) -> inhibits CYP3A -> cyclosporin can become toxic bc of decreased clearance by CYP3A

86
Q

Renal transplant with Tb exposure

A

Tx
Tb prophylaxis with Rifampicin -> Rifampicin is CYP3 INDUCER -> rapid metabolism by CYP3 -> need to increase cyclosporin dosage so it’s not cleared as fast.

87
Q

Anchoring Effect

A

Entrenched/preexisting beliefs are hard to change

88
Q

Adenoviruses

A

nonenveloped double stranded DNA virus

89
Q

replacement of gene products

A

Enzyme replacement: Lysosomal storage diseases, alpha-1-antitrypsin

• Protein Replacement: Factor replacement in hemophilia

90
Q

women aren’t good at…
men aren’t good at…
referring to genetics

A

women -> not good at sorting chromosomes

Men- > not good at sequencing (errors)

91
Q

What inhibits CYP3A

A

Grapefruit Juice
Ketoconazole (for fungal infections)

  • -> less clearance of cyclosporine (immunosuppressant)
  • –> less clearance of Felodipine (antiHTN)

—>buildup of drugs occur increasing effects

92
Q

What induces CYP3A

A

Rifampicin (RNA Pol inhbitor that prevents RNA elongation)

–> so increased clearance of cyclosporin in a renal transplant pt getting rifampicin —> must increase dosage of cyclosporin transiently while rifampicin is being administered.

93
Q

Double Heterozygote

A

An individual who has two different gene mutations (i.e., is heterozygous) at two separate genetic loci

My M2M (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions