Parasexuality
Parasexuality referred to in the genetics a reproduction of an animal by the transfer of genetic information ( DNA ) without sexuality in the strict sense, ie without fusion of gametes and without subsequent meiosis . The word parasexuality is derived from the ancient Greek para “next to”, “deviating from” and sexuality . The phenomenon of parasexuality was first demonstrated in Griffith's experiment in 1928 .
Parasexuality occurs in prokaryotes such as Eu bacteria , cyanobacteria and archaea as well as among the imperfect fungi . Parts of the genome - and thus the genetic information - from a donor cell are transferred to a recipient cell (receptor cell) and recombined there in the course of mitotic divisions . It is always a unidirectional transfer of the genetic material.
There are different ways in which a piece of donor DNA gets into a recipient cell:
- Transformation : A recipient cell takes up free DNA fragments from the environment through the cell wall and cell membrane ; then recombination occurs.
- Conjugation : A plasmid-containing donor cell transfers its plasmid via a plasma bridge ( sexpilus ) into a recipient cell .
- Transduction : a bacterial cell takes up the DNA of a bacteriophage ; the subsequent recombination creates a recombinant bacterial cell.