Question

(a) What are zygotic genes, and when are their gene products made? (b) What is the phenotype associated with zygotic gene mutations? (c) Does the maternal genotype contain zygotic genes?

Short answer

Answer: Zygotic genes are genes that are expressed in the zygote, the initial cell formed during fertilization in sexually reproducing organisms. These genes are significant in embryonic development as they are crucial for proper cell division, tissue formation, and overall growth and development of the organism. Mutations in zygotic genes can lead to a variety of phenotypes, including developmental abnormalities or even lethality in the embryo.

Step-by-step solution

Understanding zygotic genes

Zygotic genes are genes that are expressed in the zygote, which is the initial cell formed when two individual gametes (sperm and egg cells) fuse during fertilization in sexually reproducing organisms. The gene products of zygotic genes are made during the development of the embryo when the zygote undergoes cell division and differentiation.

Phenotype associated with zygotic gene mutations

Zygotic gene mutations can lead to a variety of phenotypes depending on the specific gene involved and the effect of the mutation. Generally, these mutations can result in developmental abnormalities, malformations, or even lethality in the embryo. This is because zygotic genes are crucial for proper cell division, tissue formation, and overall growth and development of the organism.

Presence of zygotic genes in the maternal genotype

Yes, the maternal genotype contains zygotic genes. A genotype refers to the complete set of genes present in an organism, including both maternal and paternal genes. Zygotic genes are present in both parental genotypes, and they are contributed to the zygote during fertilization. However, the expression or activation of zygotic genes in the developing embryo occurs independent of the maternal genotype.