Complete question:
In a population of toads, the average body length is 30mm. Body length is variable and the narrow sense heritability for body length is 0.1 for this population. You cross a male of 20mm with a female of 22mm. In order to determine the expected average offspring length, what do you multiply with your heritability?
- 30mm
- 9mm
- 0.1
- 8mm
- -9mm
- -0,5
Answer:
The correct option is -9mm
In order to know the expected average offspring length, OABL, we need to multiply the selection differential, SD ( -9mm) with narrow-sense heritability, h² (0.1).
Explanation:
<u>Available data:</u>
- the average body length, ABL, is 30mm
- the narrow-sense heritability, h², for body length is 0.1
- male of 20mm
- female of 22mm
To answer this question, we need to remember how can we calculate the selection differential and the heritability in the narrow sense.
- We can get the selection differential, SD, by getting the difference between the mean value of a population length, ABL, and the mean value of the parents of the next generation, PABL. So, in this example the selection differential is:
SD = (20mm + 22mm)/2 - 30mm
SD = 21 mm - 30mm
SD = - 9mm
- The heritability in the narrow sense, h², for body length in the population is
h² = body lengths of the offspring average/selection differential
But we already know the value of h². And we want to know the body length of the offspring. So we just need to clear the following equation.
<em>OABL = ABDL + h² ( PABL - ABL)</em>
where,
- offspring average body lengths = OABL
- population average body length = ABL = 30mm
- parents average body length = PABL = 22mm
- Selection diferential = SD = -9mm
- narrow sense heritability = h² = 0.1
OABL = ABDL + h² ( PABL - ABL)
OABL = ABDL + h² ( SD)
OABL = 30mm + 0.1 ( -9mm)
OABL = 30mm + (-0.9 mm)
OABL = 21 mm
In order to know the expected average offspring length, OABL, we need to multiply the selection differential, SD ( -9mm) with narrow-sense heritability, h² (0.1).
