An article entitled, “Androgenesis: a review through the study of the selfish shellfish Corbicula spp. has been published in the June issue of Heredity108, 581-591. K Van Doninck and associates have shown that there is duplication of chromosome number of the male clam species. This mode of aggressive asexual reproduction accounts for the widespread occurrence of clam speciesthroughout the world.
While it is a rare phenomenon in animals, in plants haploids bearing paternal characters are common. They may be obtained through anther culture. In animals such as clam species, the maternal nuclear genome do not take part in the development of zygote. As a result offspring are paternal in all their characteristics. The genus Corbicula is characterized by obligate androgenesis and found in only a few species of Corbicula. In the formation of sperm, the chromosome number remains unreduced.
After fertilization, the maternal nuclear chromosomes are eliminated as two polar bodies. Interestingly, the distribution of clam species is worldwide and its reproduction is through androgenesis. On the other hand, their sexual relatives have limited distribution. The multiplication through androgenesis is ascribed to their ubiquitous success. The authors have reviewed the phenomenon of androgenesis highlighting their evolutionary routes.