You discover a certain species of weed growing in soil contaminated with toxic P

Question

You discover a certain species of weed growing in soil contaminated with toxic PCBs, and later determine that the PCB resistance is due to a single dominant allele. SHOW YOUR WORK!

a) If 15% of the seeds from a randomly-mating population of resistant weeds will germinate in contaminated soil, what is the frequency of the PCB-resistance allele?

b) Among all the plants that germinate, what proportion will be heterozygous?

c) What proportion will be homozygous dominant?

d) If the equilibrium frequency of the dominant resistance allele is that given in "a" above, then what would be the mutation rate from the wild-type (recessive) allele to the dominant mutant allele?

Explanation / Answer

a) According to Hardy- Weinberg's law,

frequency of dominant allele is p, frequency of recessive allele is q, and p+q =1

Frequency of PCB- resistance allele = 0.15 =p

b) "2pq" proportion will be heterozygous.

q= (1- 0.15) = 0.85

2pq = (2* 0.15 * 0.85) = 0.255

c) p2 will be homozygous dominant = (0.15 * 0.15) = 0.0225

d) q = 0.85 is the mutation rate.

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.