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Heterothallic species have sexes that reside in different individuals. The term is applied particularly to distinguish heterothallic fungi , which require two compatible partners to produce sexual spores, from homothallic ones, which are capable of sexual reproduction from a single organism.
Homothallic refers to the possession, within a single organism, of the resources to reproduce sexually; [1] i.e., having male and female reproductive structures on the same thallus. The opposite sexual functions are performed by different cells of a single mycelium. [2] It can be contrasted to heterothallic. It is often used to categorize fungi.
Homothallic species are able to mate with themselves, while in heterothallic species only isolates of opposite mating types can mate. Mating between isogamous fungi may consist only of a transfer of a nucleus from one cell to another. Vegetative incompatibility within species often prevents a fungal isolate from mating with another isolate.
Sex allocation theory also applies to flowering plants, which can be dioecious, simultaneous hermaphrodites, have unisexual plants and hermaphroditic plants in the same population, have unisexual flowers and hermaphroditic flowers on the same plant or to have only hermaphroditic flowers.
These fungi are said to be homothallic, versus the normal heterothallic species with mating types. Others are secondarily homothallic, in that two compatible nuclei following meiosis migrate into each basidiospore, which is then dispersed as a pre-existing dikaryon. Often such species form only two spores per basidium, but that too varies.
This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms.It is intended as introductory material for novices; for more specific and technical definitions from sub-disciplines and related fields, see Glossary of cell biology, Glossary of genetics, Glossary of evolutionary biology, Glossary of ecology ...
Heterothallic matings are initiated by fusion of haploid cells (gametes) from two strains of opposite mating type. This contrasts with homothallic strains that appear to express both mating types. [7] Mating is initiated by gametogenesis that produces small, motile gametes that fuse to form a small binucleate cell. The volume of the binucleate ...
The species Mortierella alpina was found to be homothallic and to form zygospores with a hyphal coat. Most Mortierella species have been found to be heterothallic and to produce naked zygospores with unequal suspensors. Very often sexual structures differ in size between mating types.