What is the probable genotype of a healthy individual who is a carrier of a lethal allele but is unaffected by it?
Answer (2)
If a healthy individual is a carrier of a lethal allele but is unaffected by it, this suggests that the lethal allele is recessive and that the individual must be heterozygous for the allele. In this case, the normal or wild-type allele is dominant and masks the effect of the lethal recessive allele when present in a single copy. Such an individual would have a genotype represented by 'Aa', where 'A' is the dominant wild-type allele and 'a' is the recessive lethal allele.
Carriers do not express the phenotype associated with the lethal allele because the wild-type allele functions sufficiently to sustain life. This scenario is consistent with a recessive lethal inheritance pattern, in which homozygous recessive individuals ('aa') do not survive, but heterozygous carriers ('Aa') do and can potentially pass the allele to their offspring. Due to natural selection, recessive lethal alleles are more likely to persist in a population via these carriers.
A healthy carrier of a lethal allele likely has a heterozygous genotype 'Aa', where 'A' is the dominant allele masking the effects of the recessive lethal allele 'a'. Individuals with this genotype can pass on the lethal allele without being affected due to the recessive nature of the allele. Thus, they remain healthy while being carriers of the lethal allele.
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