Inbreeding Flashcards
What is inbreeding?
Inheritance of identical maternal and paternal chromosome segments
What makes a population particularly prone to inbreeding
Being small and/or having mating between close relatives
Does inbreeding increase or decrease homozygosity
Increases
What is used to measure the amount of inbreeding
The inbreeding coefficient (f)
What is inbreeding depression
The increase of deleterious alleles occuring homozygously in a population
What is identity by descent
Measures relatedness (R)between individuals
Coefficient of relatedness (r.) for parent-offspring (assume parents are outbred), siblings, cousins, grandparents
0.5, 0.5, 0.125, 0.25
What is the relationship between r and f
r is ½ of f
What are some drawbacks to using pedigrees toe estimate relatedness/inbreeding
-May not be a pedigree
-Pedigree may be wrong
-Pedigree may only go back a few generations
-They are just estimates–we don;t know the actual amount of genetic material being shared (eg it’s not perfectly 50-50)
How to calculate relatedness from genotyping (basics)
Find all shared haplotypes/runs of homozygosity (ROH) longer than 1Mb
Find the portion of the genome that is shared (fROH)
*This usually captures inbreeding traits captured in the last ~100 generations
Does inbreeding affect Hardy-Weinberg
Yes. Please let there be a nice question like this on the exam
How is the inbreeding coefficient calculated
f=(Hhw - H)/Hhw
H= observed heterozygosity
Hhw = expected heterozygosity inder hardy weinberg
What bummers are associated with inbred dogs
Inbred dogs have a shorter lifespan, poorer health, and worse reproduction (smaller litters, worse fertility)
Is inbreeding harmful
Not necessarily. Only when it unmasks harmful recessive variants
Is inbreeding a good way to purge deletrious alleles?
No! Your dogs will look like the Spanish royal family. Use genetic testing like an adult
