Uniparental

Uniparental refers to the inheritance of genetic material from a single parent, as opposed to biparental inheritance from both parents. The term is commonly used in genetics to describe the transmission patterns of organelle genomes, such as mitochondria and chloroplasts, which are typically passed on from one parent only.

In most animals, mitochondrial DNA is transmitted maternally, meaning offspring inherit mitochondria from the mother. In many plants, chloroplast genomes are also inherited from a single parent, usually the mother, in seed plants; however, there are exceptions where paternal inheritance occurs or where inheritance can be more complex. Rarely, organisms exhibit paternal leakage or other deviations from strict uniparental transmission.

Some groups show more unusual forms of uniparental inheritance. Doubly uniparental inheritance, observed in certain bivalves, involves two distinct mitochondrial lineages transmitted through eggs and sperm separately. These atypical patterns illustrate the diversity of inheritance mechanisms beyond standard maternal or paternal transmission.

Because organelle genomes are typically uniparentally inherited, uniparental markers are valuable for evolutionary and population genetics studies. Mitochondrial DNA is widely used to trace matrilineal lineages and to infer historical population dynamics, while Y-chromosome markers are used for patrilineal lineage analysis in species where the Y is passed from father to son. Nuclear genes, by contrast, are generally biparentally inherited, making uniparental inheritance a distinctive feature of organellar genetics and a useful tool in anthropology, forensics, and phylogenetics.