What is parthenogenesis?
What is parthenogenesis?
Some kind of animals can produce new animals from unfertilised eggs of the females. This type of reproduction is called Parthenogenesis. We can now say that the process of reproduction in which a new animal is produced from an unfertilised egg of the female animal is called Parthenogenesis.
Usually an un-fertilised ovum develops into a new individual only after the union with the sperm or fertilisation but in certain cases the development of the egg takes place without the fertilisation. This peculiar mode of sexual reproduction in which egg development occurs without the fertilisation is known as the parthenogenesis (Gr., parthenos = virgin; genesis = origin).
The phenomenon of parthenogenesis occurs in different groups of the animals as in certain insects (Hymenoptera, Homoptera, Coleoptera), crustaceans and rotifers.
how it works:-
There are several ways to theoretically circumvent this: meiosis of the sex cells can simply be stopped from happening and replaced by mitosis, leading to clones (apomixis). Another way is to start off the meiotic cycle with an already-duplicated set of chromosomes, so the result is a diploid gamete; this has no name, since it's only theoretical and hasn't actually been observed. Otherwise, a common way is automixis, whereby the post-meiosis egg duplicates its genome or fuses with one of the polar bodies. This is what happens in parthenogenetic fish and in most parthenogenetic reptiles.
Keep in mind that in other animals where sex determination works differently, parthenogenesis can be much easier, although the mechanism is unknown. I'm referring to hymenopterans (ants, bees, wasps), who are haplodiploid: females come from fertilised eggs (diploid sexuals) and males from unfertilised eggs (haploid parthenogens). How this works on the cellular level isn't known though.
Some kind of animals can produce new animals from unfertilised eggs of the females. This type of reproduction is called Parthenogenesis. We can now say that the process of reproduction in which a new animal is produced from an unfertilised egg of the female animal is called Parthenogenesis.
Usually an un-fertilised ovum develops into a new individual only after the union with the sperm or fertilisation but in certain cases the development of the egg takes place without the fertilisation. This peculiar mode of sexual reproduction in which egg development occurs without the fertilisation is known as the parthenogenesis (Gr., parthenos = virgin; genesis = origin).
The phenomenon of parthenogenesis occurs in different groups of the animals as in certain insects (Hymenoptera, Homoptera, Coleoptera), crustaceans and rotifers.
how it works:-
There are several ways to theoretically circumvent this: meiosis of the sex cells can simply be stopped from happening and replaced by mitosis, leading to clones (apomixis). Another way is to start off the meiotic cycle with an already-duplicated set of chromosomes, so the result is a diploid gamete; this has no name, since it's only theoretical and hasn't actually been observed. Otherwise, a common way is automixis, whereby the post-meiosis egg duplicates its genome or fuses with one of the polar bodies. This is what happens in parthenogenetic fish and in most parthenogenetic reptiles.
Keep in mind that in other animals where sex determination works differently, parthenogenesis can be much easier, although the mechanism is unknown. I'm referring to hymenopterans (ants, bees, wasps), who are haplodiploid: females come from fertilised eggs (diploid sexuals) and males from unfertilised eggs (haploid parthenogens). How this works on the cellular level isn't known though.
