Height in humans depends on the action of many genes whose alleles act additivel
ID: 51807 • Letter: H
Question
Height in humans depends on the action of many genes whose alleles act additively. Assume that height is controlled by four loci R, S, T, and U and that environmental effects are negligible. Assume that each capitalized allele contribute two units to an individual's height, and each lowercase allele contributes one unit to height.
Part A
Can two individuals of moderate height produce offspring that are taller or shorter than either parent? If so, how?
Can two individuals of moderate height produce offspring that are taller or shorter than either parent? If so, how?
Part B
If an individual with the minimum height specified by these genes marries an individual of intermediate or moderate height, will any of their children be taller than the tall parent? Why or why not?
If an individual with the minimum height specified by these genes marries an individual of intermediate or moderate height, will any of their children be taller than the tall parent? Why or why not?
Yes, the example of the crossing is: RRSSTTUU×RrSsTtUu Yes, the example of the crossing is: RRSSttuu×rrssTTUU Yes, the example of the crossing is: rrSsTtuu×RrSsTtUu No.Explanation / Answer
1. Yes, the example of the crossing is: rrSsTtuu×RrSsTtUu
Yes, for the given case it is possible that taller or shorter offsprings are born to two parents of moderate height. Segregation is responsible for producing different types of gametes. Thus, offsprings from cross rrSsTtuu×RrSsTtUu where both the parents are of moderate height can be born in the range of very tall (RrSSTTUu) to very short (rrssttuu).
2. No, there is no way the offspring can have more uppercase alleles than the tall parent.
In the given case if the minimum height individual marries an individual of intermediate height which is RrSsTtUu, then the offspring cannot be taller than the tall parent because of the segregation of alleles together for small or medium height.
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