Nonrandom Mating

Question 0

Inbreeding

Answer 0

Mating among genetic relatives

Question 1

Assortative mating

Answer 1

Similar individuals are more likely to mate than expected by chance (more homozygotes and fewer heterozygotes than expected)

Question 2

Selfing

Answer 2

A form of inbreeding, mate only with members of the same genotype (aa x aa or AA x AA or Aa x Aa only)

Question 3

Phenotypic assortative mating

Answer 3

“Likes attract”, type of assortative mating, increase homozygosity just at that gene

Question 4

Disassortative mating

Answer 4

Dis-similar individuals are more likely to mate than expected by chance (more heterozygotes and fewer homozygotes than expected)

Question 5

Outbreeding

Answer 5

Avoid mating with genetic relatives, type of disassortative mating

Question 6

Phenotypic disassortative mating

Answer 6

“Opposites attract”, type of disassortative mating

Question 7

Identical by descent

Answer 7

When two alleles are identical because both were inherited from a sing copy of that allele in a common ancestor

Question 8

Inbreeding coefficient (F)

Answer 8

A way to measure inbreeding, the probability that an individual taken at random from a population will have alleles that are identical by descent

Question 9

Inbreeding depression (delta)

Answer 9

Inbreeding + selection, reduction in fitness of inbred individuals relative to outbred individuals caused by expression of deleterious recessive alleles in homozygous genotypes

Question 10

Purging

Answer 10

The removal of deleterious alleles by selection, inbreeding benefits since it can remove deleterious alleles when they become present in homozygotes

Question 11

Nonrandom mating affect in allelic diversity and frequencies

Answer 11

Acting alone does not change allelic frequencies (not a mechanism of evolution) but rather changes genotype frequencies, decrease heterozygosity and thus decreases allelic diversity

Question 12

Mechanism of evolution?

Answer 12

No

Question 13

Affect on genotype frequencies

Answer 13

Changes them

Question 14

Assortative mating affect on genotype

Answer 14

Decrease in heterozygosity

Question 15

Disassortative mating affect on genotype

Answer 15

Increase heterozygosity

Question 16

Violate Hardy-Weinberg equilibrium principle?

Answer 16

Yes

Question 17

Inbreeding affect on genotype

Answer 17

More homozygotes and fewer heterozygotes than expected

Question 18

Inbreeding alone affect allelic frequencies?

Answer 18

No, affects genotype frequencies only

Question 19

Calculate F

Answer 19

Use H = 2pq(1-F) where 2pq is the expected frequency of heterozygotes in a population with ransom mating at H-W eq and F is the fractional reduction in heterozygosity in an inbred population compared with a randomly mating population, high F means high levels of inbreeding (closer to 1)

Question 20

Range of F

Answer 20

0-1

Question 21

High vs low F

Answer 21

High F means higher inbreeding meaning that heterozygosity is decreased significantly and homozygotes are in excess relative to H-W, low F means lower inbreeding meaning heterozygosity and homozygous numbers are relatively normal in relation to H-W

Question 22

Two processes involved in inbreeding depression

Answer 22

Inbreeding and selection

Question 23

Inbreeding depression genetic explanation

Answer 23

An excess number of homozygotes are produced and homozygotes might have different fitness from heterozygotes, recessive deleterious alleles (normally hidden in heterozygotes) can come together in homozygous inbred offspring and be expressed

Question 24

Calculate inbreeding depression (delta)

Answer 24

Delta = 1-(wi/wo) where wi is the fitness of inbred individuals and wo is the fitness of outbred individuals

Question 25

Factors affecting inbreeding depression

Answer 25

1. Environmental stress - more severe under stressful situations
2. Stage of life cycle - effects may only show later in life
3. Degree of inbreeding - selling > sibling > cousin
4. Current frequencies of deleterious alleles in family or population

Question 26

Long term inbreeding

Answer 26

Populations that have been inbreeding/selfing for a long time have less inbreeding depression since selection had already purged deleterious alleles and so they are no longer hidden in a heterozygous state

Question 27

Purging and allele frequencies

Answer 27

Over time purging reduces magnitudes of inbreeding depression by removing deleterious recessive alleles, if inbreeding occurs for a long time population may no longer feel any negative effects

Question 28

How organisms avoid inbreeding depression?

Answer 28

Outbreeding and disassortative mating through mate choice, genetically controlled self comparability and dispersal, small inbreeding populations may not be able to avoid (conservation concern)

Question 29

Phenotypic assortative mating changing genotype frequencies

Answer 29

Based on underlying genotype similarity this can also lead to an increase in homozygotes for that trait