Question

Q11. In a circumstance in which a population was subjected to migration from an outside group, the B allele of the ABO blood system was determined to be 0.11 in natives, 0.55 in migrants, and 0.19 in the conglomerate population. What is the migration rate, m?

Answer 1

Migration refers to gene flow; i.e, movement of genes between populations.

Migration rate(M) is the proportion of immigrants in a population after migration.

M = (No.of migrants)/(Total no. of individuals after migration)

Migration alters frequency of alleles in a population.

We are asked to calculate the migration rate from the allele frequencies of B allele of ABO system before and after migration.

The new allele frequency after migration is given by the equation:

p' = (1-M)p + Mp"

Where,

• p' is the allele frequency of conglomerate population(after migration)
• p is the allele frequency of residents
• p" is the allele frequency of migrant population
• M is the migration constant

Given that

p' = 0.19

p = 0.11

p"= 0.55

Substitution of these values in the above equation;

0.19 = (1-M)×0.11 + M × (0.55)

0.19 =[ 0.11 - 0.11M] + 0.55 M

0.19 =0.11 + 0.44M

0.44M = 0.19 - 0.11

           = 0.08

Therefore, M = 0.08/0.44

                     = 0.18

Thus, the migration rate is 0.18; meaning that 18% of the total population after migration are migrants.