Principle Of Genetics Inheritance Flashcards

1
Q

Genes

A

Segments of DNA in a chromosome

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2
Q

Locus

A

The specific place of a gene

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3
Q

Chromatin

A

One of two identical copies of a chromosome

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4
Q

Centromere

A

Connects identical sister chromatids

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5
Q

Telomere

A

Region at the end of the chromosome for stability

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6
Q

Somatic cells

A

Diploid cells that are differentiated

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7
Q

Homologous chromosomes

A

2 copies of each gene with the order of 4 loci being identical

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8
Q

Auto some

A

Chromosomes common in both genders, and you get one from each parent

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9
Q

Metacentric

A

Centromere is in the center of the chromosome

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10
Q

Submetacentric

A

Just off the center. A short arm (P) and a long arm (Q)

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11
Q

Acrocentric

A

Off center; very little information on the short arm so could be removed and the chromosome still functions normally

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12
Q

17q11.2

A
17: chromosome number
Q: arm
1: region
1: band
2: subband
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13
Q

Karyotype

A

entire set of patient’s chromosomes

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14
Q

Lyonization

A

X-inactivation; chromosome that is inactivated is random

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15
Q

Mosaicism

A

Condition in which cells from a patient have different genotypes in different areas of the body

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16
Q

Stem cells

A

Undergo mitosis but will divide asymmetrically, resulting in one stem cell and one daughter cell

17
Q

Homologous recombination

A

Genes will switch locations so that the homologous chromosomes are not identical. Changes the sequence of alleles that are passed from generation to generation for genetic diversity

18
Q

Euploid

A

Cells with a normal number of chromosomes

19
Q

Polyploidy

A

Cells with missing or additional individual chromosomes

20
Q

Reciprocal NH chromosome exchange

A

An exchange of material between non homologous chromosomes

21
Q

Robertsonian exchange

A

Long arm of two acrocentric chromosomes will combine, leading to loss of the short arm

22
Q

Nondisjunction

A

Chromosome pairs do not split up, resulting in fertilization of zygotes with trisomy or monosomy.

23
Q

Prayer Willie syndrome

A

Paternal deletions of region of chromosome 15. Results in short stature, hypotonia, small hands/feet, obesity, and mild to moderate mental disability

24
Q

Angel man syndrome

A

Maternal deletion of region of chromosome 15. Results in severe intellectual disability, seizures, and ataxic gait.

25
Q

Klinefelter Syndrome

A

47,XXY
Varying levels of symptoms depending on # of excess X. Varying degrees of cognitive/social difficulties. Hypogonadism, small testes, tall stature, infertility, and can be mosaic

26
Q

Trisomy 13, 18, 21

A

47, XX +21: Down syndrome. Increased risk w/ maternal age
47, XX+13: Patau syndrome. Severe developmental abnormalities and often results in perinatal death w/in 1 week
47, XX+ 18: Edwards syndrome. Leads to abnormal development and perinatal death w/in 1 year

27
Q

Proband (propositus)

A

First person diagnosed in a pedigree

28
Q

Penetrance

A

Frequency a gene is expressed. Can be 100% or less. In retinoblastoma, 90% of those with the gene express the phenotype so that is 90% penetrance

29
Q

Variable expressively

A

A range of phenotypes will vary between individuals with a specific genotype

30
Q

Locus heterogeneity

A

A single disorder, trait, or pattern of traits caused by mutations in genes at different chromosomal loci

31
Q

Probability multiplication rule

A

Probability of a given outcome in multiple trials is the product of the probabilities of each trial outcome

Probability of three girls: 1/2+1/2+1/2=1/8

32
Q

Probability addition rule

A

Probability of either one outcome or the other is the sum of two probabilities

Probability of three girls or three boys: 1/8 + 1/8 = 1/4

33
Q

Hardy Weinberg Principles

A

Shows relationship between gene frequencies and genotype frequencies.

Know frequency of A (p) and deduce a (q) to be 0.7 and 0.3 respectively. Determine population frequency of each genotype AA, Aa, and aa

AA: p^2=0.49
Aa: q^2=0.09
Aa: 2pq = 2(0.21)=0.42

34
Q

Consanguineous mating

A

More likely to produce offspring affected by rare recessive disorders.

35
Q

Leber’s hereditary optic neuropathy

A

Mitochondrial disorder. Causes degeneration of retinal ganglion cells and an acute or subacute loss of central vision —> typically in early teens or 20’s

36
Q

Mitochondrial encephalomyopathy, lactic acidosis, and stoke like episodes (MELAS)

A

Mitochondrial disorder. Affects many body systems, but mainly the brain, nervous system, and muscles.

Stoke and dementia and lactic acidosis.

37
Q

Multifactorial inheritance

A

Environmental factors and genetics cause variation in the trait —> multifactorial