03-08-2007, 11:04 AM
Hi all!
I am a lame spammer and I like to be beaten with large trouts...but I'm not here to talk about me. Let's talk about parthenogenesis
Parthenogenesis is a form of asexual reproduction in which females produce eggs that develop without fertilization. Parthenogenesis is seen in aphids, daphnia, rotifers, and some other invertebrates, as well as in some plants. Among vertebrates, there are several genera of fish, amphibians, and reptiles that exhibit differing forms of asexual reproduction, including true parthenogenesis, gynogenesis, and hybridogenesis (an incomplete form of parthenogenesis).
The offspring of parthenogenesis will be all female if two like chromosomes determine the female sex (such as systems where XX is female and XY is male), but male if the female sex is determined by unlike chromosomes (such as systems where WZ is female and ZZ is male), because the process involves the inheritance and subsequent duplication of only a single sex chromosome. The offspring may be capable of sexual reproduction, if this mode exists in the species. A parthenogenetic offspring is sometimes called a parthenogen. As with all types of asexual reproduction, there are both costs (reduced genetic diversity generated and susceptibility to adverse mutation) and benefits (reproduction without the need for a male) associated with parthenogenesis.
Parthenogenesis is distinct from artificial animal cloning, a process where the new organism is identical to the cell donor. Parthenogenesis is truly a reproductive process which creates a new individual or individuals from the naturally varied genetic material contained in the eggs of the mother. A litter of animals resulting from parthenogenesis may contain all genetically unique siblings without any twins or multiple numbers from the same genetic material. Parthenogenic offspring of a parthenogen are, however, all genetically identical to each other and to the mother, as a parthenogen is homozygous.
The alternation between parthenogenesis and sexual reproduction is called heterogamy. Forms of reproduction related to parthenogenesis but that require the presence of sperm are known as gynogenesis and hybridogenesis
I am a lame spammer and I like to be beaten with large trouts...but I'm not here to talk about me. Let's talk about parthenogenesis
Parthenogenesis is a form of asexual reproduction in which females produce eggs that develop without fertilization. Parthenogenesis is seen in aphids, daphnia, rotifers, and some other invertebrates, as well as in some plants. Among vertebrates, there are several genera of fish, amphibians, and reptiles that exhibit differing forms of asexual reproduction, including true parthenogenesis, gynogenesis, and hybridogenesis (an incomplete form of parthenogenesis).
The offspring of parthenogenesis will be all female if two like chromosomes determine the female sex (such as systems where XX is female and XY is male), but male if the female sex is determined by unlike chromosomes (such as systems where WZ is female and ZZ is male), because the process involves the inheritance and subsequent duplication of only a single sex chromosome. The offspring may be capable of sexual reproduction, if this mode exists in the species. A parthenogenetic offspring is sometimes called a parthenogen. As with all types of asexual reproduction, there are both costs (reduced genetic diversity generated and susceptibility to adverse mutation) and benefits (reproduction without the need for a male) associated with parthenogenesis.
Parthenogenesis is distinct from artificial animal cloning, a process where the new organism is identical to the cell donor. Parthenogenesis is truly a reproductive process which creates a new individual or individuals from the naturally varied genetic material contained in the eggs of the mother. A litter of animals resulting from parthenogenesis may contain all genetically unique siblings without any twins or multiple numbers from the same genetic material. Parthenogenic offspring of a parthenogen are, however, all genetically identical to each other and to the mother, as a parthenogen is homozygous.
The alternation between parthenogenesis and sexual reproduction is called heterogamy. Forms of reproduction related to parthenogenesis but that require the presence of sperm are known as gynogenesis and hybridogenesis