What are maternal and zygotic genes?

In nearly all animals, maternal gene products regulate the initial events of embryogenesis while the zygotic genome remains transcriptionally silent. Developmental control is then passed from mother to zygote through a process known as the maternal-to-zygotic transition (MZT).

What is the maternal effect gene?

Maternal-Effect Genes Maternal genes are those genes whose products, RNA or protein, are produced or deposited in the oocyte or are present in the fertilized egg or embryo before expression of zygotic genes is initiated.

What is zygotic gene?

A gene expressed in the early embryo. Embryos with mutations in zygotic genes are phenotypically abnormal, and this phenotype is dependent on genetic contributions from both parents, i.e., upon the genotype of the zygote, rather than the genotype of the mother or the father alone. Also called zygotic effect gene.

What are the maternal effect genes in Drosophila?

Bicoid and Hunchback are the maternal effect genes that are most important for patterning of anterior parts (head and thorax) of the Drosophila embryo. Nanos and Caudal are maternal effect genes that are important in the formation of more posterior abdominal segments of the Drosophila embryo.

How is maternal effect related to zygotic effect?

Mutations in genes that are expressed in the embryo sac but whose gene products are stored cytoplasmically and function after fertilization show a maternal effect [proposed for PROLIFERA ( PRL) in Arabidopsis; S pringer et al. ( 2000 )].

When does zygotic gene activation occur after fertilization?

Zygotic gene activation (ZGA) is the first event of gene expression after fertilization. Following fertilization, ZGA occurs within a short time interval depending on the animal species. Until ZGA, maternal proteins and transcripts stored in oocytes control embryonic development, indicating the impo …

How are genes involved in the maternal effect?

This last class, gametophytic maternal effect genes, can have its effect through several distinct mechanisms. Mutations in genes required in two doses in the endosperm will show a maternal effect because the endosperm is triploid with two maternal genomes and one paternal genome ( e.g., floury3 in maize; M a and N elson 1975 ).

How does the mother affect the development of the seed?

Proper development of the seed depends not only on the action of genes from the resulting embryo and endosperm, but also on maternal genes acting at two stages. Mutations with both sporophytic maternal effects and gametophytic maternal effects have been identified.