From which parent does a male inherit his X chromosome? answer Mother

Why are X-linked recessive genes for various disorders much more frequently expressed in males than in females? answer Males have an X and a Y chromosome. The Y chromosome is much smaller than the X since it contains fewer genes. As a result, the genes on the X chromosome are often the only ones present that affect a certain trait. Consequently, even recessive genes are often expressed. On the other hand, females have two X chromosomes and, in order for a recessive gene to be expressed, she must be homozygous for that trait. However, females are often the carriers of X-linked genetic disorders.

If two traits do not follow the law of independent assortment, what might be concluded about them? answer The two traits are probably linked, meaning their gene loci are probably on the same chromosome. Further, their loci are probably quite close together so that crossing-over does not have a significant effect.

What is likely the most deleterious type of mutation? answer An insertion or deletion of one or two nucleotides near the beginning of where transcription occurs in a gene. This causes a frame-shift of almost the entire nucleotide coding sequence.