alleryStart learning →A recessive lethal inheritance pattern is one in which the allele has which effect?
AIt kills only in the homozygous form
BIt kills only in the heterozygous form
CIt kills in every possible genotype form
DIt kills only when carried by a male parent
Answer & Solution
Correct answer: A. It kills only in the homozygous form
1. Many genes are essential, so a non-functional allele can be fatal when no working copy is present.
2. A recessive lethal allele is only lethal in the homozygous form.
3. The heterozygote has a working copy and may be normal or show some altered non-lethal phenotype.
4. An allele lethal in the heterozygote as well would be a dominant lethal instead.
_Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 12 "Mendel's Experiments and Heredity", section 12.2 Characteristics and Traits_
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