amphimixis

Amphimixis is a form of sexual reproduction in which haploid gametes from two individuals fuse to form a diploid zygote. The resulting zygote contains genetic material from both parents and typically develops into an embryo through subsequent cell divisions. Amphimixis involves the union of male and female gametes and is contrasted with asexual modes such as autogamy or apomixis; in many species the gametes come from two distinct individuals, though self-fertilization can occur in some organisms.

The process is widespread across animals, plants, and many algae and fungi, though its cellular details differ. In animals, fertilization occurs when sperm meets an egg, often within the reproductive tract or in the external environment. In flowering plants, pollen delivers sperm cells to the ovule, resulting in fertilization and seed formation. In algae and fungi, fusion of compatible gametes also leads to a zygote.

Etymology and usage: amphimixis derives from Greek amphi- meaning "both" and mixis meaning "mixing." Historically, it has been used to describe fertilization that yields a zygote from two genetically distinct gametes. In modern biology, the term is frequently treated as synonymous with fertilization or syngamy, though some texts distinguish the broader concept of genetic mixing (amphimixis) from the specific cytological event of gamete fusion (syngamy).

Genetic consequences: by combining genetic material from two parents, amphimixis fosters genetic diversity through recombination and independent assortment, contributing to evolutionary adaptability.