Final answer:
A lethal gene can be recessive, dominant, or conditional, depending on the locus. Recessive lethal genes are only lethal in the homozygous form, while dominant lethal genes are lethal in both homozygous and heterozygous forms. Conditional lethal genes are only lethal under certain conditions.
Step-by-step explanation:
A lethal gene can be recessive, dominant, or conditional, depending on the locus. A recessive lethal gene is one that is only lethal in the homozygous form, meaning an individual must have two copies of the gene to experience lethality. An example of a recessive lethal gene is Tay-Sachs disease. On the other hand, a dominant lethal gene is lethal in both the homozygous and heterozygous form. Huntington disease is an example of a dominant lethal gene. Lastly, a conditional lethal gene is one that is only lethal under certain conditions, such as exposure to specific environmental factors or when combined with certain alleles. Overall, a lethal gene can exhibit different modes of inheritance depending on its nature and the specific gene locus.