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A study investigated the vitamin A content and cholesterol content of eggs from

ID: 141886 • Letter: A

Question

A study investigated the vitamin A content and cholesterol content of eggs from a large population of chickens. The variances were calculated as shown in the table below.

Trait

Variance

Vitamin A

Cholesterol

VP

123.5

862.0

VE

96.2

484.6

VA

12.0

192.1

VD

15.3

185.3

a)Calculate broad and narrow sense heritability for the two traits.

b)What do you need to assume to complete part (a.)

c)Which trait if either is likely to respond to selection best in the short term and in

the long term.

Trait

Variance

Vitamin A

Cholesterol

VP

123.5

862.0

VE

96.2

484.6

VA

12.0

192.1

VD

15.3

185.3

Explanation / Answer

Ans a)The narrow-sense heritability is defined as the ratio of additive genetic variance to the total phenotypic variance.

h2 = VA/VP

Thus, for vitamin A,

The narrow-sense heritability

h2 = 12/123.5 = 0.0971

Thus, for Cholesterol,

The narrow-sense heritability

h2 = 192.1/862= 0.2228

The broad sense heritability is expressed as the ratio of the total genetic variance to the total phenotypic variance

h2=(VG/VP).

Ans b) The broad sense heritability cannot be calculated the VG value is not given. The VG value is needed

Ans c) Cholesterol