NATIONAL OPEN UNIVERSITY OF NIGERIA

UNIVERSITY VILLAGE, PLOT 91, CASDASTRAL ZONE, NNAMDI AZIKIWE EXPRESS WAY, JABI, ABUJA.
FACULTY OF SCIENCES
OCTOBER/NOVEMBER 2019 EXAMINATION

COURSE CODE: BIO403
COURSE TITLE: POPULATION GENETICS
CREDIT: 2 Units
TIME ALLOWED: 2 Hours
INTRUCTION: Answer Question ONE (1) and any other THREE (3) Questions

1a. Define the term genetic drift. (2 marks)
b. Explain how mutation affects evolution (3 marks)
c. Is there Hardy-Weinberg population in real life? (3 marks)
d. Enumerate five assumptions upon which Hardy-Weinberg law depends. (5 marks)
e. Hemoglobin variants among Africans where multiple alleles are present are shown in the Table below.
Hemoglobin genotypes:
AA AS SS AC SC CC Total
4,034 1566 8 346 28 22 6,004
Calculate the:
i. genotypic frequencies. (6 marks)
ii. allelic frequencies. (6 marks)

2a. Highlight the significance of a Chi square test in population genetics studies (3 marks)
b. Write short notes on the following:
i. . Migration (4 marks)
ii. Selective mating (4 marks)
iii. Adaptation (4 marks)

3a. Using Equations, show how allelic frequencies at an X-linked locus can be determined from the genotypic frequencies (3 marks)
b. Give a detailed description of any three forms of genetic drift you know. (12 marks)

4a. It takes over several generations to approach equilibrium frequencies if the alleles are sex-linked and the sexes differ in allelic frequency. Discuss (8 marks)
b. The number of individuals living in a town is 600. A study showed that the number of Individuals in the town with different M-N blood group phenotypes are as follows:
Phenotype
No. of individuals
M
90
MN
150
N
60
Calculate:
i. the genotypic frequency. (4 marks)
ii. the allelic frequency. (3 marks)

5a. State Hardy-Weinberg Law. (3 marks)
b. In a population of 200,000 people carrying the recessive allele, a, for albinism, there are 200 aa albinos, 196,200 AA and 3,600 Aa heterozygous carriers.
i. Compute the allelic frequencies in the parent population. (6 marks)
ii. Using Hardy-Weinberg equation, predict the number of individuals of each genotype in the next generation. (6 marks)