Information AboutApomixis |
| CATEGORIES ABOUT APOMIXIS | |
| plant reproduction | |
|
As apomictic plants are genetically identical from one generation to the next, each has the characters of a true Species , maintaining distinctions from other Congeneric apomicts, while having much smaller differences than is normal between species of most Genera . They are therefore often called microspecies. In some genera, it is possible to identify and name hundreds or even thousands of microspecies, which may be grouped together as '''aggregate species''', typically listed in Flora s with the convention "''Genus species'' agg." (e.g., the Bramble , ''Rubus fruticosus'' agg.). Good examples of apomixis can be found in the genera '' Crataegus '' (hawthorns), '' Sorbus '' ( Rowan s and Whitebeam s), '' Rubus '' (brambles or blackberries), ''Hieracium'' ( Hawkweed s) and ''Taraxacum'' ( Dandelion s). A unique example of male apomixis has recently been discovered in the Saharan Cypress, '' Cupressus Dupreziana '', where the seeds are derived entirely from the Pollen with no genetic contribution from the female "parent" (Pichot, et al., 2000, 2001). In Zoology '' Parthenogenesis '' is the Animal equivalent of apomixis. Recently, Matthew Meselson won the Lasker Award 2004. He and his students are probing why sex is necessary for evolution. Some small aquatic animals, Bdelloid Rotifers , are apomictic and have survived for millions of years without sex. They serve as an experimental model system. Meselson assumes that the advantage of sex may lie in its ability to reduce what he calls "genetic parasites" (i.e. Transposable Elements ). These are pieces of DNA that multiply on their own and can cause genetic damage. Bdelloid rotifers don't appear to have such parasites. SEE ALSO REFERENCES IN POPULAR CULTURE The patenting of apomixis is the MacGuffin at the core of British journalist Peter Pringle's thriller The Day of the Dandelion (Simon & Shuster, 2007). FURTHER READING
REFERENCES
|
|
|