The maternal-effect mutation bicoid (bcd) is recessive. In the absence of the bicoid protein product, embryogenesis is not completed. Consider a cross between a female heterozygous for the bicoid alleles (bcd⁺/bcd⁻) and a male homozygous for the mutation (bcd⁻/bcd⁻).

How is it possible for a male homozygous for the mutation to exist?

Video transcript

Everyone. Let's take a look at this question together, mutation of the bike hygiene can cause development failure of the interior segment of the developing fly embryo. However, it can only be expressed when what, let's recall what we've learned about mutations in the bike hygiene to figure out when it is expressed. So we know that the biker jeans are a maternal effect jean which is responsible for the development of the interior segment of a fly embryo. And when we have a mutation in that gene it's a mutation leads to development failure and because it is a maternal effect gene that means that it is a responsibility of the mother. So answer choices C. And D. Are incorrect and it is only expressed when the mother is mama's I guess or the mutation because the mother has to be home as august for that mutation to be expressed and when the mother is hetero suggest there is no gene expression. So answer choice A. Is the correct answer and it is not answer choice B. Because mutations of the bike hygiene which caused development failure of the anterior segment of a developing fly embryo are only expressed when the mother is home. As I guess for that mutant allele, which is answer choice A. The correct answer. I hope you found this video to be helpful. Thank you and goodbye