A horse has 64 chromosomes and a donkey has 62 chromosomes. A cross between a female horse and a male donkey produces a mule, which is usually sterile. How many chromosomes does a mule have? Can you think of any reasons for the fact that most mules are sterile?

While working in the lab, you notice that your fruit flies all appear to have an intersex phenotype. This is most likely due to: O There being a 2:3 ratio of X chromosomes to autosomal chromosomes. O There being a 1:2 ratio of X chromosomes to autosomal chromosomes. O There being a 3:2 ratio of X chromosomes to autosomal chromosomes. O There being a 1:1 ratio of X chromosomes to autosomal chromosomes. O There being a 1:2 ratio of Y chromosomes to autosomal chromosomes.

Draw two replicated, condensed, homologous chromosomes that have the genes E and F on them. This individual is heterozygous for gene E, and homozygous recessive for gene F. Be sure to label your chromosomes for full credit.

A gene has 3 alleles. How many different genotypes are possible in this locus in a diploid organism?

What is the possible number of gamete cells that can be produced from a diploid 2n=4 taking crossing-over into account?

So why the barr bodies cannot be seen in the experiment?

The white spots in this image represent Barr Bodies. The cells are from a Male cell line. What is the sex chromosome complement of this cell line?