increased homozygosity

Inbreeding reduces heterozygosity…
With the most extreme inbreeding (self-fertilization),
heterozygosity is reduced by half each generation:
For a population where all individuals self-fertilize:
Genotypes:
A 1 A 1 A 1 A 2 A 2 A 2
All homozygotes
All homozygotes
A 1
A 1 A 2
A 2
A 1 A 1 A 1 A 2
A 1 A 2 A 2 A 2
A 1 A 1 (25%)
A 1 A 2 (50%)
A 2 A 2 (25%)
Only 50% of the progeny of heterozygotes will be heterozygous
Inbreeding reduces heterozygosity…
We can estimate the level of inbreeding within a population by
comparing observed heterozygosity with the heterozygosity
expected for random mating (Hardy-Weinberg expectation: 2pq).
F =
Inbreeding coefficient
H expected - H observed
H expected
where H expected = 2pq
(F= 1: complete inbreeding)
(F< 0: avoidance of inbreeding)
2