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POPULATION GENETICS Flashcards

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1
Q

The study of the rules governing the maintenance and transmission of genetic variation in natural populations.

A

Population Genetics

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2
Q

Many more individuals are born than survive

A

Competition

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3
Q

Individuals within species are variable

A

Variation

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4
Q

Some of these variations are passed on to offspring

A

Heritability

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5
Q

Survival and reproduction are random. There must be a correlation between fitness and phenotype.

TRUE OR FALSE?

A

FALSE. Survival and reproduction are NOT random. There must be a correlation between fitness and phenotype.

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6
Q

the complete set of genetic information in all individuals within a population.

A

Gene pool

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7
Q

proportion of individuals in a population with a specific genotype

A

Genotype frequency

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8
Q

Genotype frequencies may coincide from one population to another.

TRUE OR FALSE?

A

FALSE. Genotype frequencies may DIFFER from one population to another.

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9
Q

proportion of any specific allele in a population

A

Allele frequency

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10
Q

Allele frequencies are estimated from gene pool.

TRUE OR FALSE?

A

FALSE Allele frequencies are estimated from GENOTYPE FREQUENCIES.

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11
Q

In Population Genetics, evolution can be defined as a change in gene frequencies through time.

TRUE OR FALSE?

A

TRUE.

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12
Q

Population genetics tracks the time, across generations, of Mendelian genes in populations.

TRUE OR FALSE?

A

FALSE. Population genetics tracks the FATE, across generations, of Mendelian genes in populations.

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13
Q

Population genetics is concerned with whether a particular allele or genotype will become more or less common over time, and WHY.

TRUE OR FALSE?

A

TRUE

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14
Q

When gametes containing either of two alleles, A or a, unite at random to form the next generation, the genotype frequencies among the zygotes are given by the ratio.

A

Hardy-Weinberg Principle

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15
Q

These variables or formula that constitutes the Hardy-Weinberg Principle.

A

p = frequency of a dominant allele A

q = frequency of a recessive allele a

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16
Q
  • The population is sufficiently large
  • Mating is random
  • Allelic frequencies are the same in males and females
  • Selection does not occur = all genotypes have equal in viability and fertility
  • Mutation and migration are absent
A

Hardy-Weinberg Principle

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17
Q
  • Mating is random (with respect to the locus).
  • The population is infinitely large. (no sampling error - Random Genetic Drift)
  • Genes are not added from outside the population (no gene flow or migration).
  • Genes do not change from one allelic state to another (no mutation).
  • All individuals have equal probabilities of survival and reproduction (no selection).
A

Hardy-Weinberg Assumptions

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18
Q

Based on HW Principle, A random mating population with no external forces acting on it will reach the equilibrium H-W frequencies in a single generation, and these frequencies remain constant there after.

TRUE OR FALSE?

A

TRUE

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19
Q

Based on HW Principle, Any perturbation of the gene frequencies leads to a new equilibrium after random mating.

TRUE OR FALSE?

A

TRUE

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20
Q

According to HW Principle, The amount of heterozygosity is minimized when the gene pools are intermediate.

TRUE OR FALSE?

A

FALSE. The amount of heterozygosity is MAXIMIZED when the gene FREQUENCIES are intermediate.

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21
Q

One important implication of HW principle is that allelic frequencies will remain constant overtime if the following conditions are met.

TRUE OR FALSE?

A

TRUE

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22
Q

Another implication of HW principle is that, for a rare allele, there are many more homozygotes than there are heterozygotes for the rare allele.

TRUE OR FALSE

A

FALSE. Another important implication is that for a rare allele, there are many more HETEROZYGOTES than there are HOMOZYGOTES for the rare allele.

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23
Q

FOUR PRIMARY USES OF THE H-W PRINCIPLE:

A
  • Enables us to compute genotype frequencies from generation to generation, even with selection.
  • Serves as a null model in tests for natural selection, nonrandom mating, etc., by comparing observed to expected genotype frequencies.
  • Forensic analysis.
  • Expected heterozygosity provides a useful means of summarizing the molecular genetic diversity in natural populations.
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24
Q

Fisher united Mendelian population genetics with the inheritance of continuous traits

A

The Genetical Theory of Natural Selection (1930)

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25
Q

Developed the mathematical theory of gene frequency change under selection (and many other interesting applications).

A

J.B.S Haldane

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26
Q

He developed the mathematical framework for understanding the
genetic consequences of migration, effective population size, population subdivision, and conceived of the concept of adaptive landscapes.

A

Sewall Wright

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27
Q
  • J.B.S. Haldane - Developed the mathematical theory of gene frequency change under selection (and many other interesting applications).
  • Sewall Wright developed the mathematical framework for understanding the
    genetic consequences of migration, effective population size, population
    subdivision, and conceived of the concept of adaptive landscapes.
A

The causes of Evolution (1932)

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28
Q
  • Populations contain genetic variation that arises by random mutation.
  • Populations evolve by changes in gene frequency.
  • Gene frequencies change through random genetic drift, gene flow, and natural selection.
  • Most adaptive variants have small effects on the phenotype so changes are typically gradual.
  • Diversification comes about through speciation.
A

Outcomes of the “Modern Synthesis”

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29
Q

the origin of new genetic capabilities in populations = the ultimate source of genetic variation

A

Mutation

30
Q

the process of evolutionary adaptation = genotypes best suited to survive and reproduce in a particular environment give rise to a disproportionate share of the offspring

A

Natural selection

31
Q

the movement of organisms among subpopulations

A

Migrations

32
Q

the random, undirected changes in allele frequencies, especially in small populations

A

Random genetic drift

33
Q

Changing Allele Frequencies

A

Evolution

34
Q

Organisms differ in their ability to survive and reproduce, and some of these differences are due to genotype

A

Selection and Fitness

35
Q

the relative ability of genotypes to survive and reproduce

A

Fitness (W)

36
Q

measures the comparative contribution of each parental genotype to the pool of offspring genotypes in each generation

A

Relative fitness

37
Q

refers to selective disadvantage of a disfavored genotype

A

Selection coefficient

38
Q

Selection can affect
frequencies quite rapidly

TRUE OR FALSE?

A

TRUE

39
Q

Frequency of favored dominant allele changes slowly if allele is common

A

Selection in Diploids

40
Q

Frequency of favored recessive allele changes slowly if the allele is rare

A

Selection in Diploids

41
Q

Rare alleles are found most frequently in heterozygotes

A

Selection in Diploids

42
Q

When favored allele is dominant, recessive allele in heterozygotes is not exposed to natural selection

A

Selection in Diploids

43
Q
  • Frequency of favored dominant allele changes slowly if allele is common
  • Frequency of favored recessive allele changes slowly if the allele is rare
  • Rare alleles are found most frequently in heterozygotes
  • When favored allele is dominant, recessive allele in heterozygotes is not exposed to natural selection
A

Selection in Diploids

44
Q

fitness (measurement of viability and fertility) of heterozygote is greater than that of both homozygotes

A

Heterozygote superiority

45
Q

When there is heterozygote superiority, neither allele can’t be eliminated by selection.

TRUE OR FALSE?

A

FALSE. When there is heterozygote superiority, neither allele CAN be eliminated by selection

46
Q

In sickle cell anemia, allele for mutant hemoglobin is maintained in high frequencies in regions of endemic malaria because heterozygotes are more resistant to to this disease

TRUE OR FALSE?

A

TRUE

47
Q

Some changes in allele frequency are random due to genetic drift

A

Random Genetic Drift

48
Q

It comes about because populations are not infinitely large

  • Only relatively few of the gametes participate in fertilization = sampling
  • With random genetic drift, the probability of fixation of an allele is equal to its frequency in the original population
A

Random Genetic Drift

49
Q

It means mating between relatives

A

Inbreeding

50
Q

It results in an excess of homozygotes compared with random mating

A

Inbreeding

51
Q

In most species, inbreeding is harmful due to rare recessive alleles that wouldn’t otherwise become homozygous

TRUE OR FALSE?

A

TRUE

52
Q

application of genetic principles to entire populations of organisms

A

Population genetics

53
Q

group of organisms of the same species living in the same geographical area

A

Population

54
Q

any of the breeding groups within a population among which migration is restricted

A

Subpopulation

55
Q

subpopulation within which most individuals find their mates

A

Local population

56
Q

Cumulative genetic change in a population through time

A

Evolution

57
Q

A progressive increase in the degree to which as species become genetically well suited to its environment.

A

Adaptation

58
Q

The principle mechanism of Adaptation

A

Natural selection

59
Q

Individuals superior in survival or reproductive ability in the prevailing environment contribute a disproportionate share of genes to future generations

A

Natural selection

60
Q

heritable change in a gene

A

mutation

61
Q

movement of individuals among subpopulations

A

migration

62
Q

which results from chance sampling due to restricted population size

A

random genetic drift

63
Q

These rates are generally so low that the effect of mutation on changing allele frequency is minor, except for rare alleles

A

Spontaneous mutation

64
Q

What is the main effect of Migration?

A

The tendency to equalize allele frequencies among the local populations that exchange migrants

65
Q

Occurs through differences in viability, (the probability of survival of a genotype) and in fertility (the probability of successful reproduction)

A

Selection

66
Q

the probability of survival of a genotype

A

viability

67
Q

the probability of successful reproduction

A

fertility

68
Q

a statistical process of change in allele frequency in small populations, resulting from the inability of every individual to contribute equally to the offspring of successive generations

A

Random genetic drift

69
Q

(NOT A Q&A)

Population maintains harmful alleles at low frequencies as a result of a balance between selection, which tends to eliminate the alleles, and mutation, which tends to increase their frequencies. When there is selection-mutation balance, the allele frequency at equilibrium is usually greater if the allele is completely recessive than if it is partially dominant.

A

This difference arises because selection is quite ineffective at influencing the frequency of a completely recessive allele when the allele is rare, because of the almost exclusive appearance of the allele in heterozygotes.

70
Q

It means mating between relatives

A

inbreeding

Genetics (8 decks)

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