Question

LAB EXERCISE 4.1 continued Name 9 In a population of 500 people, 160 are homozygous dominant for tongue rolling and 90 cannot roll their tongue. a How many people are heterozygous for tongue rolling? Use the space below for doing your calculations. b List the three possible genotypes and the number of people that have each. c Keeping in mind that each individual has two alleles for the trait, how many dominant alleles for tongue rolling are in the gene pool? d many recessive ones are there?

Answer 1

9.a

160 ozygous 90 mber of how qualy 500-250 homo Total Total population size homo z your zygous recessive 250 500 - 950

b. If we consider the dominant gene for rolling as R, the recessive allele for not rolling as 'r', homozygous dominant rollers are" RR", Heterozygous rollers are "Rr", homozygous non-tollers are "rr".

c. Dominant alleles are paired in homozygous dominant (RR), there are 160 homozygous dominant individuals.

Homozygous dominant individual has ---160 x 2 = 320.

Heterozygous rollers will have only one dominant allele, there are 250 heterozygous individuals.

So, total dominant alleles in the population are ---320 + 250 = 570

d. The recessive alleles in the population is ---

Heterozygous Rollers wil have 1 allele. So there 250 recessive alleles in heterozygous individuals.

Number of homozygous non-rollers is 90 and each non-roller will have 2 recessive allelels.

So, total recessive alleles in the population is 250 + 180 = 430