Population genetics


Gene I (AB0 blood system) exists in three forms - IA, IB and i. What are the genotype and phenotype frequencies in panmictic population, if frequency of allele IB (q) = 0.4 and frequency of allele i (r) = 0.4?


    In humans, three types of earlobes can be found. In a group of 100 students, free earlobe (hanging free from the head) was found in 38 students (genotype dominant homozygotes), middle attached in 45 students (heterozygotes) and attached (joined to the head) in 17 students (recessive homozygotes).
  1. What are the frequencies of dominant and recessive alleles?
  2. Use χ2 test to verify, if population is in HW equilibrium (table values are here).


Population is in HW equilibrium. Frequency of allele (b) for blue color of eyes is 0.6. What is the frequency of blue-eyed people in the population? How many % of brown-eyed people with homozygote and heterozygote genotypes are in this population?


In population, there is 36 % blue-eyed people (bb) and 64% brown-eyed people (BB, Bb). How many % of brown-eyed homozygotes and brown-eyed heterozygotes are there?


In humans, the presence of RhD antigen (named after rhesus monkey), determines the blood type. If the antiserum against this antigen agglutinates your red blood cells you are Rh+ (Rh positive) (genotype DD or Dd), if it doesn't you are Rh- (Rh negative) (genotype dd). In the Central European Caucasian population, approximately 84 % of people are Rh+ and 16 % Rh-. What is the frequency of the dominant allele?


Frequency of recessive allele (a) for myopy (short sightedness) in a population is q (a) = 0.14. What are the frequencies of short-sighted people (genotype aa) and of healthy carriers (genotype Aa) in this population?


    Albinism is recessively inherited disorder (inability to synthesize pigment melanin). In the population, there is one albino (aa) in 10 000 people (the frequency of genotype aa is 0.0001).
  1. What is the allelic frequency of recessive allele a?
  2. How many % of carriers (Aa) are present in this population?