Assume a population of pea plants consists of 300 TT and 700

Assume a population of pea plants consists of 300 TT and 700 tt, with T (tall) dominant to t (short).

A. What are the phenotypic, genotypic, and allele frequencies?

B. Further assume that you allow this population to undergo one generation of random mating with eachother and you know that mutation is very rare, there is no selection happening, and the population is large enought that drift is negligible. You count the number of tall plants to be 382 and the number of short plants to be 368. What is the genotypic frequency of this generation? What is the allele frequency?

C. Was the original population in Hardy Weinberg equilibrium?

D. Did any evolution occur from one generation to the next?

Solution

Assume a population of pea plants consists of 300 TT and 700 tt, with T (tall) dominant to t (short).

A. What are the phenotypic, genotypic, and allele frequencies?

TT

300

P^2

Homozygous

Dominant

tt

700

q^2

Homozygous

recessive

1000

By using square root method

q^2 =700/1000=0.7

q^2 ==0.7

q=square root of 0.7= 0.836----------------------recessive allele frequency

p+q=1

p=1-0.836=0.164----------dominant allele frequency

genotypic frequency

Number

TT

P^2

Homozygous

Dominant

0.164 x 0.164=0.026896

0.164 x 0.164 x 1000=26

Tt

2pq

Heterozygous

2x 0.164x 0.836 =0.274208

2x 0.164x 0.836 x1000=274

q^2

Homozygous

recessive

0.836 x 0.836 =0.698896

0.836 x 0.836 x 1000=700

Tt

1000

1000

B. Further assume that you allow this population to undergo one generation of random mating with eachother and you know that mutation is very rare, there is no selection happening, and the population is large enought that drift is negligible. You count the number of tall plants to be 382 and the number of short plants to be 368. What is the genotypic frequency of this generation? What is the allele frequency?

368+382=

By using square root method

q^2 =368/750=0.49

q^2 ==0.49

q= 0.7----------------------recessive allele frequency

p+q=1

p=1-0.7=0.3----------dominant allele frequency

frequency

Number

TT

P^2

Homozygous

Dominant

0.3 x 0.3=0.09

0.09 x 750=67.5=67

Tt

2pq

Heterozygous

2x 0.3x 0.7=0.42

0.42x750=315

q^2

Homozygous

recessive

0.7 x 0.7 =0.49

0.49x 750=367.5=368

Tt

750

1

1000

original population is NOT Hardy Weinberg equilibrium

As there is change in frequency of alleles one generation to next generation.

TT	300	P^2	Homozygous Dominant
tt	700	q^2	Homozygous recessive
	1000