stejnosmrný

Stejnosmrné is a term used in reproductive biology to describe organisms that produce gametes which are morphologically similar in size and appearance, so there is no distinct male or female gamete. The concept corresponds to the English term isogamy. In stejnosmrné systems, fertilization occurs when two compatible, similarly appearing gametes fuse, often after recognition of mating types or chemical signals rather than through a clear separation into sperm and egg.

This reproductive mode is found in a variety of lineages, particularly among certain algae, protists, and some fungi. In these organisms, both mating types produce gametes that resemble one another, and sexual identity is defined by compatibility rather than by visible differences in gamete form. Gametes are frequently motile, often flagellated, but the key feature remains their indistinguishable morphology.

Stejnosmrné life cycles typically include a haploid phase in which gametes are produced by individuals of each mating type, followed by fertilization that yields a diploid zygote. Depending on the species, the zygote may immediately undergo meiosis or pass through a short diploid stage before returning to haploid phases.

From a scientific perspective, stejnosmrné serves as a reference point for studying the evolution of sexual reproduction and the development of mating recognition without pronounced gamete dimorphism. It helps researchers compare the dynamics of genetic recombination and fertilization across organisms that lack distinct gamete types.

See also: isogamy, anisogamy, oogamy, sexual reproduction in algae and fungi.