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Here is a NY Times article and a Science magazine news article about the crayfish taking over Europe.
Genomes have been sequenced.
It has 3 sets of chromosomes from two different animals (both belonging to the same species). The two parental animals were not closely related.
The two sets of chromosomes from the same animal were virtually identical indicating that they were the result of a doubling of a single chromosome set (or from a very inbred population).
Two chromosome sets from one parent and one from the other makes the resulting crayfish a triploid (three chromosome sets). Triploids are often unfertile.
This crayfish is somehow just making triploid eggs that can start developing without any genetic input from the males. Thus they are doing parthanogenisis. (Some parthogenetic species are require sperm from a closely related species to poke the egg and get development going, some do not.)
These crayfish are supposed to be large, fecund (makes a lot of eggs), and better able to adapt to differeing conditions. They are looking at why that is.
Because they are being produced parthanogenetically, they are all genetic clones of the original. they have lost the ability to mix their genomes up when they breed. This is supposed to limit their long term evolutionary viability because useful new mutations arise rarely and are limited to the clonal lineage of the animals they arose in rather than mixing more widely in the population.
From fish breeding studies it known that triploid fish are made in some fish farms in part because they make bigger fish. That are also sterile (non-invasive) and divert resources to meat production (profit).
Another parallel to fish breeding is they are the result of crossing two distinct genetic groups together (the two parental crayfish). The resulting animal has a lot of heterozygosity at lots of different genetic loci. These are the conditions for producing hybrid vigor, Where you cross together two different genetic lines and the first generation does super well because to has so much heterozygosity, but crosses among the first generation can not maintain the levels of heterozygosity, and those animals are more like their parents. (There are arguments about whether its is really the heterozygosity driving this, but its an OK description).
Both of these conditions are preserved in these crayfish since the are only making clones of themselves. They are triploids (good) and very heterozygous (also good) forever.
Genomes have been sequenced.
It has 3 sets of chromosomes from two different animals (both belonging to the same species). The two parental animals were not closely related.
The two sets of chromosomes from the same animal were virtually identical indicating that they were the result of a doubling of a single chromosome set (or from a very inbred population).
Two chromosome sets from one parent and one from the other makes the resulting crayfish a triploid (three chromosome sets). Triploids are often unfertile.
This crayfish is somehow just making triploid eggs that can start developing without any genetic input from the males. Thus they are doing parthanogenisis. (Some parthogenetic species are require sperm from a closely related species to poke the egg and get development going, some do not.)
These crayfish are supposed to be large, fecund (makes a lot of eggs), and better able to adapt to differeing conditions. They are looking at why that is.
Because they are being produced parthanogenetically, they are all genetic clones of the original. they have lost the ability to mix their genomes up when they breed. This is supposed to limit their long term evolutionary viability because useful new mutations arise rarely and are limited to the clonal lineage of the animals they arose in rather than mixing more widely in the population.
From fish breeding studies it known that triploid fish are made in some fish farms in part because they make bigger fish. That are also sterile (non-invasive) and divert resources to meat production (profit).
Another parallel to fish breeding is they are the result of crossing two distinct genetic groups together (the two parental crayfish). The resulting animal has a lot of heterozygosity at lots of different genetic loci. These are the conditions for producing hybrid vigor, Where you cross together two different genetic lines and the first generation does super well because to has so much heterozygosity, but crosses among the first generation can not maintain the levels of heterozygosity, and those animals are more like their parents. (There are arguments about whether its is really the heterozygosity driving this, but its an OK description).
Both of these conditions are preserved in these crayfish since the are only making clones of themselves. They are triploids (good) and very heterozygous (also good) forever.