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Flashcards in Population & quantitative genetics Deck (4)
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1

A newly identified recessive genetic condition called Developmental Duplication, or DD, has been confirmed and brought to members' attention by Angus Australia this week.

a) given that developmental duplication is recessive and there have been approximately 20 calves born with the defect out of 1,000,000 calves born in total, what is the frequency of the defect allele?

recessive, therefore q^2

q^2 = 20/1,000,000

       = 0.00002

q = sqrt(0.00002) = 0.00447

therefore, p = 1 - q = 1 - 0.00447 = 99.53

2

What proportion of the population would be expected to be carriers?

carriers = heterozygous individuals = 2pq = 2 * 99.53 * 0.00447 = 0.890

3

Briefly describe what you would expect the effect of inbreeding would be on the proportion of carriers and calves with developmental duplication. Why?

inbreeding increases homozygosity = more affected individuals (homozygous recessive) = less carriers

4

If across the Angus cattle breed there were just 10 sires widely used among the elite studs because of the large use of artificial insemination, demonstrate using equations and calculations that even there are 200,000 dams, inbreeding could still become a problem.

s = 10 d = 100,000 Ne = 4sd/s+d = (4*10*100,000)/(10+100,000) = (4,000,000)/(100,010) = 39.996