Question

A population of monkeyflowers (Mimulus guttatus) with a mean flower width of 25 mm is studied; in this population, the narrow-sense heritability for flower width is estimated to be 0.3. If two plants are selected from this population that have flower lengths of 30 mm and 34 mm and crossed, what would the expected mean flower length of their progeny be?

a.) 32.0 mm

b.) 25.0 mm

c.) 27.1 mm

d.) 22.9 mm

Answer 1

If we have determined the narrow-sense heritability of a trait and know several population values we can estimate the phenotypic value for an offspring. The following formula can be used for the prediction.

To = T + h2(T*-T) where

To = predicted offspring phenotype
T = population mean
h2 = narrow sense heritability
T* = midparent value [(Tf + Tm)/2]

We need to find To

T = 25

Tf = 30

Tm= 34

T* = [(30+34)/2 ] = 32

h2 = 0.3

Then

To = 25 + 0.3( 32-25) = 27.1

The expected mean flower length of their progeny = 27.1