Question

In fruit flies, the allele for ebony body color is a nonlethal, recessive mutation. The table below shows the number of ebony and brown fruit flies, over several generations, in a population for which only the ebony and brown alleles are present.
Generation Brown Body Ebony Body
1 490 4
2 857 7
3 612 5
4 367 3
6 980 8
Is evolution occurring in this population? Explain your answer using the Hardy-Weinberg equation.

PLEASE HELP! I need someone who can help me understand how to apply the Hardy-Weinberg equation here!!!

Answer 1

In the first generation, there are 490 brown fruit flies and 4 ebony fruit flies. This mean that the frequency of the brown (p2) is 490/490+4 = 0.992 and the frequency of the ebony (q2) is 4/490+4 = 0.008. The frequency of the dominant allele is p=√0.992=0.995 and the frequency of the recessive allele is q=√0.008=0.089. p+q=1 (HW)

The Hardy-Weinberg equilibrium principle describes that frequency of alleles is unchanged through the generations.

Gen 2.  

p2= 857/857+7=0.991

q2=7/857+7=0.008

Gen 3.

p2= 612/612+5=0.991

q2=5/612+5=0.008

Gen 4.

p2= 367/367+3=0.991

q2=3/367+3=0.008

Gen 5.

p2= 980/980+8=0.991

q2=8/980+8=0.008

The frequency of alleles is unchanged, population is not evolving.