The mutant strain maroon-like has an X-linked mutant allele (Xm) that results in deep maroon-colored eyed in homozygous females and hemizygous males. To prove to a skeptical friend that this trait is in fact X-linked you set up a reciprocal cross against the wild type. What are the expected genotypic and phenotypic frequencies of each half of this crossing experiment?

See the answer below

Explanation:

From the illustration, maroon-like mutant strain is represented by the allele m and it is X-linked. Homozygous females () and hemizygous males () have the maroon trait and are mutants.

A reciprocal cross is made against the wild type. The wild type would be homozygous for the alternate from of the gene in females and hemizygous for alternate form of the gene in males.

Crossing a wild type female with a mutant male (first half);

  x  

Progeny =

Genotypic ratio: 1 : 1

Phenotypic ratio: All wild type

Crossing a mutant female with a wild type male (second half);

  x  

Progeny =

Genotypic ratio: 1 : 1

Phenotypic ration: 1 wild type : 1 mutant

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!