autogamia

Autogamia, from the Greek auto- meaning self and gamos meaning marriage, is a reproductive mode in which fertilization occurs using the genetic material from the same individual. In biology the term is used most often to describe self-fertilization, particularly in plants, but it also refers to certain cellular-level processes in ciliates and other organisms that achieve a form of self-reproduction.

In plants, autogamy occurs when pollen from the same flower or the same plant fertilizes its own ovules. This can happen through self-pollination within a flower or through mechanisms such as cleistogamy, where flowers never open and pollen is automatically delivered to ovules. Self-compatibility, arising in many lineages, allows selfing to proceed, while self-incompatibility systems can prevent it by blocking pollen from the same plant or flower. Autogamy is contrasted with geitonogamy (pollination between flowers of the same plant) and allogamy (outcrossing with other individuals).

In other organisms, autogamy can refer to self-fertilization or to self-derived nuclear processes that restore a diploid state. In ciliates such as Tetrahymena and Paramecium, autogamy is a nuclear reorganization that occurs within a single cell, where haploid nuclei fuse to form a new, genetically varied somatic nucleus. In hermaphroditic animals, self-fertilization can occur when an individual possesses both male and female reproductive functions.

Evolutionarily, autogamy reduces genetic diversity and heterozygosity but can ensure reproduction when mates are scarce or conditions are stable. It often drives selection for self-compatibility and can be a route to colonization or persistence in isolated populations.