ch 7- heredity Flashcards

1
Q

locus

A

locaition of a gene on a chromosome

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2
Q

gene

A

sequence of DNA that codes for a trait

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3
Q

allele

A

variation of a gene

found at the same loci on both chromosomes in a homologous pair

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4
Q

wild type allele

A

normal allele most common in nature

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5
Q

mutation

A

HERITABLE change in DNA

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6
Q

hemizygous

A

only one allele is present

example- men only have one X and one Y chromosome which contain hemizygous genes

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7
Q

penetrance

A

proportion of individuals who have the phenotype associated with a specific allele

complete penetrance- the gene for a trait is expressed in all the population who have the gene

incomplete penetrance- the genetic trait is expressed in only part of the population

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8
Q

expressivity

A

the degree of a certain phenotype for a given genotype

every kid has curly hair, but the curls look different

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9
Q

incomplete dominance

A

heterozygous will have intemediate state

ex. red and white make pink

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10
Q

example of multiple alleles

A

there are more than two allele options- ex, blood typing

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11
Q

epistasis

A

one gene affects the expression of a different gene

ex baldness covers the gene for the colour of hair

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12
Q

pleitoropy

A

one gene is responsible for many traits

ex. cystic fibrosis gene rewsponsible for many symptoms

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13
Q

polygenic inheritance

A

many genes responsible for one trait

gives the trait continous variation

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14
Q

haploinsufficiency

A

one copy of the gene is lost and the expression of the remaining copy is not sufficient enough to have normal phenotype

results in intermediate phenotype

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15
Q

proto oncogenes

A

can become oncogenes due to GAIN OF FUNCTION mutations

follow one hit hypothesis

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16
Q

gain of function mutations

A

cause too much protein to be made or production of an over active protein leading to cancerous growth

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17
Q

one hit hypothesis

A

gain of function mutation in one copy of the gene turns it into an oncogene

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18
Q

tumor supressor genes

A

become cancerous due to loss of function mutations

two hit hypothesis

haplosufficient !!

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19
Q

two hit hypothesis

A

loss of function mutation is needed in both copies of the gene to make it cancerous

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20
Q

null alleles

A

come from mutations that lead to a lack of normal function in alleles - tumor supressor genes have null alleles when they become cancer causing

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21
Q

p53

A

tumor supressor gene that is known as the guardian of the cell

upregulated to prevent cells from becoming cancerous

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22
Q

p21

A

another tumor supressor gene that inhibits phosphorylation activity to decrease rampant cell division

23
Q

retinoblastoma gene

A

tumor supressor gene that codes for retinoblastoma protein

prevents excessive cell growth during interphase

24
Q

what are the three laws of gregor mendel

A

law of dominance
law of segregation
law of independent assortment

25
law of segregation
homologous gene copies separate during meiosis anaphase I Aa individual produces gametes with A and a alleles
26
law of independent assortment
Homologous chromosomes line up independently during metaphase I of meiosis so that alleles separate randomly (this increases genetic variability). The law of independent assortment can produce 2^23 options (23 homologous chromosome pairs split).
27
non disjunction
improper segragatino of chromosome pairs during anaphase single nondisjunction of chromosomes during meiosis i single nondisjunction of chromosomes during meiosis II single nondisjunction of chromosomes during mitosis
28
single nondisjunction of chromosomes during meiosis i
24, 24, 22, 22
29
single nondisjunction of chromosomes during meiosis II
24, 22, 23, 23
30
single non disjunction in mitosis
47, 45
31
aneuploidy
abnormal number of chromosomes in the daughter cell which leads to trisomy or monosomy after fertilization disomy- normal diploid cell
32
down syndrome
trisomy of the 21st chromosome each diploid cell have 47 chromosomes total
33
turner syndrome
monosomy of the X chromosome in females each diploid cell has 45 chromosomes physical abnormalities and sterility
34
klinefelters syndrome
trisomy of the sex chromosomes in males giving XXY and 47 chromosomes intelectual issues physical issues and reproductive issues
35
trisomy x
trisomy of x chromosomes in females learning disabilities and attention issues
36
test cross
pairs an individual of unkown genotype with one that is homozygous recessive
37
where can mendels three laws be studied
in the f2 generation
38
dihybrid cross
examines the inheritance of two genes on separate chromosomes
39
females and males on pedigree charts
females- cicles males- square
40
recombinant vs non recombinant gametes
recombinant- receive gentically unique chromatids nonrecombinant- receive parental chromatids- did not undergo crossing over
41
linked genes
found close tog on the same chromosome deduce relative distance between genes by looking at recombination frequencies
42
map unit
1% of recombination bw two genes (1cM- centrogram)
43
recombination frequency of _ means genes are linked
less than 50% means they are linked
44
when genes are perfectly linked, they have a recombination frequency of
0
45
linkage maps
tables used to determine the probability of inheritance use map units to infer distance between genes on a chromosome
46
haplotype
group of genes usually inherited tog bc they are close to each other on the chromosome
47
epigenetics and twins
cause monoxygous twins to have different susceptibilities to the same disease
48
genomic imprinting
genes expressed depending on parental origin - influenced by epigenetic factors only one copy of gene in individual expressed- either from mom or dad and the other is expressed diff from sex linked triats bc they come from autosomal chromosomes (non sex chromosomes)
49
histone methylation vs DNA methylation
histone methylation- either upregulate or downregulate DNA methylation- supresses gene expression - prevent transcription factors from binding
50
x linked dominiant
Dominant inheritance on the X chromosome. Any offspring (male or female) that receive the affected allele will end up with the disorder.
51
x linked recessive
Recessive inheritance on the X chromosome. For males, only one affected allele is needed to cause the disorder. For females, two affected alleles are needed to cause the disorder because females have two X chromosomes. Hemophilia and color-blindness are examples of X-linked recessive conditions.
52
y linked
Inheritance on the Y chromosome. Can only be passed from father to son. Will always be expressed whether it is dominant or recessive because males only have one Y chromosome.
53
x inactivation
process by which one of females x chromosomes is inactivated forming a Barr body and preventing excess transcription female carrier can become affected for a disease if her unaffected x vhromosome with wild type allele is inactivated