Question

Evolutionary Genetics

Buy using the Hardy - Weinberg Law: A real life example

On September 27, 1996 The NweYork Times reported onan allel(R) that confered complete resisance to HVI when homozygous

* 1% of the human population is resistant (RR)

* The NY Times reported that 20% of the allel (ie , was heterozygous).

?? 1. Is this a guess, an approximation, or an exact frequncy??

??2.What is the allele frequencyof p? q?

??3. What is the genotype frequency of the heterozygous??

Answer 1

Frequency of homozygous resistant (RR) = 1% or 0.01

Frequency (p) of dominant allele (R) = ?(0.01) = 0.1

According to Hardy-Weinberg law,

p + q = 1

where p and q are frequencies of dominant (R) and recessive (r) alleles respectively.

q = 1 - 0.1 = 0.9

Frequency of heterozygotes (Rr) = 2pq = 2 x 0.1 x 0.9 = 0.18 or 18%.

1. Since 18% (calculated heterozygous frequency ) is close to 20% (reported heterozygous frequency), it is an approximation.

2. Allelic frequencies: p = 0.1, q = 0.9.

3. Genotype frequency of heterozygous = 0.18 or 18%.