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Flashcards in Final - Population Genetics Deck (30)
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1
Q

Population genetics

A
  • the study of the distribution of genes in populations and how the frequencies of genes and genotypes are maintained or changed from generation to generation
2
Q

Population

A
  • local group of organisms belonging to a single species

- composed of interbreeding individuals who share a common gene pool

3
Q

Gene Pool

A
  • the set of genes contained in an entire population
4
Q

Allele frequency

A
  • frequency of an allele in a population, as measured by its percentage of the total number of alleles at a particular gene locus
5
Q

Genotype frequency

A
  • percentage of individuals in a population who are homozygous or heterozygous for an allele at a particular locus
6
Q

Hardy Weinberg Law

A
  • can be used to determine allele and gentotype frequencies in a population.
  • states these frequencies remain constant from one generation to the next under 5 conditions
7
Q

5 conditions of Hardy Weinberg Law

A
  1. Large population size
  2. Random mating between individuals in the population
  3. No mutations in the alleles
  4. No migration into or out of the population
  5. No natural selection (i.e. all genotypes are equally viable and fertile)
8
Q

Equation for Allele Frequency

A

p + q = 1

A) (a

9
Q

Equation for genotype frequency

A

p^2 + 2pq + q^2 = 1

(AA) (Aa) (aa)

10
Q

Equation for Frequency of Allele from genotype Frequency

A

Freq (allele) = Freq (homozygote) + 1/2 Freq (heterozygote)
B = BB + 1/2 Bb
p = p^2 + 1/2 pq

11
Q

Frequency of phenotype => genotype => allele

A

p = Sqrt (p^2)

a aa

12
Q

Recessive allele Frequency in males

A

= phenotype frequency, since males have only 1 X chromosome

13
Q

Applications of Population genetics

A
  1. Use in genetic Counseling
  2. To plan genetic screening programs
  3. In molecular diagnostics testing
14
Q

Consanguineous Mating

A
  • interbreeding

- 2 individuals who share a common ancestor preceeding 2 or 3 generations

15
Q

Assortive Mating

A
  • based on factors like race, ethnic groups, culture differences, religious beliefs, intelligence, language
16
Q

Inbred

A
  • children from the result of consanguineous mating
17
Q

Founder effect

A
  • occurs when a population is formed by a small group of individual
  • alleles carried by these “founder” are established in the new population
  • ex: discovery of new island
18
Q

Population bottleneck

A
  • change in gene frequency that occurs when a population is suddenly reduced in size and then expands again
  • ex: natural disaster = volcano
19
Q

Genetic drift

A
  • random changes in allele frequencies from generation to generation in small population
  • caused by founder effect and population bottleneck
20
Q

Fitness

A
  • a measure of the relative survival and reproductive success of a specific individual or genotype
21
Q

Race

A
  • a subdivision of species that has come to differ in the frequencies of alleles it possesses
22
Q

Factors leading to Change in Gene Frequencies

A
  1. Small population size
    - subject to genetic drift
    - race
  2. Non- random mating
    - assortive mating
    - consanguineous mating
  3. Natural Selection
    - fitness
  4. Mutation
  5. Migration - rapid introduction of new alleles
23
Q

Heritability

A
  • the degree to which a trait is inherited
  • expressed as the proportion of variability caused by genetic differences
  • ranges from H = 0 - 1.0
24
Q

H = 1.0

A
  • genetic differences = 100% of variation

- Environmental factors = contribute to 0%

25
Q

H = 0

A
  • Environmental factors = 100% of the variation

- genetic differences = contribute to 0%

26
Q

Genetic variance

A
  • phenotypic variability in a population due to differences in genotypes
27
Q

Environmental variance

A
  • phenotypic variability in a population due to differences in environmental factors
28
Q

How monozygotic twins are used to determine heritability

A

Monozygotic= genetically identical = 100%
Dizygotic = share 50% of their genes
- if environmental factors play more of a role, the concordance value will be less than 100% in monozygotic twins and lower than 50% in dizygotic twins

29
Q

Mutation and Polymorphism

A
  • mutation rate = 1 mutation per 100,000 - 1 million copies of a gene
  • 1 in 10 people is likely to have received a new mutation
  • mutations established in > 1% of the population are known as polymorphisms
30
Q

Multifactorial Traits

A
  • traits that result from genetic variance (2 or more genes) and environmental variance (1 or more factors)
  • exhibit continuous variation, in varying degrees along a continuum
  • ex: height, weight, skin color, intelligence, diabetes mellitus, manic depression