Example 2.1 in you text describes a plumage polymorphism in Arctic skua involvin
ID: 142535 • Letter: E
Question
Example 2.1 in you text describes a plumage polymorphism in Arctic skua involving a point mutation of the MC1R gene that results in substitution of arginine for histadine in the resulting protein. Thus, genotypes (and their corresponding phenotypes) can be specified Arg/Arg (pale), Arg/His (intermediate), and His/His (dark). Suppose you observed the following numbers of progeny among a large number of nesting pairs: 2. Nesting Pair Progeny intermediate 4 Male Female pale intermediate dark intermediate dark dark pale dark pale pale 73 0 0 pale intermediate intermediate 59 37 17 43 56 dark 0 Which progeny cannot be the offspring of observed nesting pairs? Explain your answer. [It may help to substitute genotypes for the terms pale, intermediate, and dark in the table above.] The progeny identified in A could be the result of 'extra-pair copulation' in which a nesting female produces one or more eggs sired by a male other than her nest-mate or 'egg- dumping' in which a female lays one or more eggs in the nest of another nesting pair. Explain the evidence for one or both processes based on the data above. A. B.Explanation / Answer
A. First progeny cannot be offspring of observed nesting pair because in this case the nesting pairs are both pale, so the progeny they should produce would be pale only but they are producing intermediate and dark progeny also.
B. The progeny resulted in A could be the result of extra pair copulation as well egg dumping.
Extra pair copulation occurs when monogamous species pair mates outside of this pairing. This could result in the plumage polymorphism among progeny.
Egg dumping is when females lays her egg in the nest of other birds. This could also results in the different type of progeny from the observed nesting pairs.
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