Question

Part C If loss of bicoid function in the egg leads to lethality during embryogenesis, how are females homozygous for bicoid produced? O Homozygous bicoid mutant females (and males) can be produced by crossing male and female +/bicoid heterozygotes. O Homozygous bicoid mutant females (and males) can be produced by crossing male and female +/bicoid heterozygotes. In order to develop normally, the eggs resulting from this cross should be supplied with normal bicoid protein. This can be achieved by introducing a plasmid, which provides for transient expression of bicoid protein. O Homozygous bicoid mutant females (and males) can be produced only as the result of genetic engineering. O Homozygous bicoid mutant females (and males) can be produced only as the result of extensive mutagenesis. Submit Request Answer Part D What is the phenotype of a male homozygous for bicoid loss-of-function alleles? Homozygous bicoid mutant males that were produced by a female heterozygous for bicoid will develop into headless embryos that do not complete development. Homozygous bicoid mutant males that were produced by a female heterozygous for bicoid will have progeny that will develop into headless embryos that do not complete development. O Homozygous bicoid mutant males that were produced by a female heterozygous for bicoid will be phenotypically normal. O Homozygous bicoid mutant males that were produced by a female heterozygous for bicoid will be sterile. Submit Request Answer

Answer 1

C) bicoid shows the maternal effect that is the phenotype of the progeny depends on the genotype of the mother if the mother is homozygous for bicoid mutation then the mother cannot give functional mRNAs of the bicoid gene to the egg cell so the embryo will have two tails, so to get homozygous mutants for the bicoid cross a male who is homozygous mutant of bicoid or heterozygous to a heterozygous female, since the mother has functional gene for the bicoid the embyro will have functional mRNA of the bicoid from the egg cell so the progeny develops to normal fly so the answer is homozygous bicoid mutant females ( males) can be produced by crossing male and female +/bicoid heterozygotes.

D) if the fly is homozygous for the loss of function mutation of bicoid will be normal becuase its mother is heteozygous for the mutation so the fly has got functional mRNA of the bicoid in the early developmental stages from the egg cell so the answer is

homozygpus bicoid mutants produced by a female heteroygous for the bicoid will be phenotypically normal.