MCAT Question of the Day
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    Q:

    		 Mice homozygous for a lethal recessive allele die shortly after birth. Taking advantage of the fact that mice breed several times a year and have large litters, an experiment establishes a breeding colony of over 1,000 mice, and surprisingly, between 4 and 6% of all newborns die from this trait. Moreover, the same proportion of offspring have been dying from this trait in this colony for the past five years. Which of the following best describes the persistence of this lethal allele at such a frequency?
    		 

    A

    		 There is a reproductive advantage for homozygous recessive mice

    B

    		 Gene flow maintains the allele at this frequency

    C

    		 Genetic drift maintains the allele at this frequency

    D

    		 There is some sort of heterozygote advantage and perhaps selection against the homozygous dominant trait.



    Evolution |
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