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In genetics, a maternal effect occurs when the phenotype of an organism is determined by the genotype of its mother. [1] For example, if a mutation is maternal effect recessive, then a female homozygous for the mutation may appear phenotypically normal, however her offspring will show the mutant phenotype, even if they are heterozygous for the mutation.
Since nuclear and cytoplasmic genes usually have different modes of transmission, intragenomic conflicts between them may arise. [18] Mitochondria and chloroplasts are two examples of sets of cytoplasmic genes that commonly have exclusive maternal inheritance, similar to endosymbiont parasites in arthropods, like Wolbachia. [19]
The idea of sex-limited genes was initially developed by Charles Darwin in 1871 in his book The Descent of Man and Selection in Relation to Sex. [6] He did not distinguish between sex-limited, sex-linked, and sex-influenced genes, but referred to any gene that expresses differently between sexes as sex-limited.
Paternal stress is an important factor in the determination of inheritance of genes as well as maternal stress inheritance. Factors such as environment and experiences can alter the epigenetic of paternal genes as well as in sperm. Epigenetic changes to the DNA in sperm ("epigenetic tags") prior to conception can be passed to offspring.
Mutations in mtDNA or other cytoplasmic DNA will also be inherited from the mother. This uniparental inheritance is an example of non-Mendelian inheritance. Plants also show uniparental mtDNA inheritance. Most plants inherit mtDNA maternally with one noted exception being the redwood Sequoia sempervirens that inherit mtDNA paternally. [46]
The CoRR hypothesis states that the location of genetic information in cytoplasmic organelles permits regulation of its expression by the reduction-oxidation ("redox") state of its gene products. CoRR is short for "co-location for redox regulation", itself a shortened form of "co-location (of gene and gene product) for (evolutionary) continuity ...
Extranuclear inheritance (also known as cytoplasmic inheritance) is a form of non-Mendelian inheritance also first discovered by Carl Correns in 1908. [9] While working with Mirabilis jalapa , Correns observed that leaf colour was dependent only on the genotype of the maternal parent.
Human embryonic development or human embryogenesis is the development and formation of the human embryo.It is characterised by the processes of cell division and cellular differentiation of the embryo that occurs during the early stages of development.