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you discover a certainspecies of weed growing in soil contaminated with toxic PC

ID: 5674 • Letter: Y

Question

you discover a certainspecies of weed growing in soil contaminated with toxic PCBS, andlater determine that the PCB resistance is due to a single dominantallele. A) if 15% of the seeds from a randomly-mating population ofresistant weeds will germinate in contaminated soil, what is thefrequency of the PCB-resistance allele? B)Among all the plants that germinate, what proportion will beheterozygous? C)What proportion will be homozygous dominant? D)if the equilibrium frequency of the dominant resistnaceallele is what given in "a" above, then waht would be the mutationrate from the wild-type (recessive) allele to the dominant mutantallele? you discover a certainspecies of weed growing in soil contaminated with toxic PCBS, andlater determine that the PCB resistance is due to a single dominantallele. A) if 15% of the seeds from a randomly-mating population ofresistant weeds will germinate in contaminated soil, what is thefrequency of the PCB-resistance allele? B)Among all the plants that germinate, what proportion will beheterozygous? C)What proportion will be homozygous dominant? D)if the equilibrium frequency of the dominant resistnaceallele is what given in "a" above, then waht would be the mutationrate from the wild-type (recessive) allele to the dominant mutantallele?

Explanation / Answer

ANSWER:

PCB resistance is due to a single dominantallele----------P

Genotypes; PP,Pp,pp

PP,Pp,---shows PCB resistance

Frequency          of genotype PP,+   Pp=15%

Frequency          of pp genotypes=85%

Frequency          of p allele = square root of .85=.92

P+p=1

So

what is the frequency of the PCB-resistanceallele?

Answer= .08

B)Among all the plants that germinate, what proportionwill be heterozygous?

Heterozygous=2pq

=2 x   .08 x .92=.1472

=14.72%

C)What proportion will be homozygousdominant?

=PX P=.08 X.08=.0064

= 0.64%