A cell that has only one set of chromosomes and thus contains no homologous chromosome pairs is called:

If a man and a woman are each heterozygous carriers of a mutation causing a disease on the RUSP list, what do you think are the three or four most important factors they should consider in their decision making about having children?

Suppose a man and a woman are each heterozygous carriers of a mutation causing a fatal hereditary disease not on the RUSP list. Prenatal genetic testing can identify the genotype of a fetus with regard to this disease and can identify fetuses with the disease. What do you think are the three or four most important factors this couple should consider in their decision making about having children?

In the wasp Bracon hebetor, a form of parthenogenesis (the development of unfertilized eggs into progeny) resulting in haploid organisms is not uncommon. All haploids are males. When offspring arise from fertilization, females almost invariably result. P. W. Whiting has shown that an X-linked gene with nine multiple alleles (Xₐ, Xb, etc.) controls sex determination. Any homozygous or hemizygous condition results in males, and any heterozygous condition results in females. If an Xₐ/Xb female mates with an Xₐ male and lays 50 percent fertilized and 50 percent unfertilized eggs, what proportion of male and female offspring will result?