A cool sniper from an article I found. What are your thoughts on this?

[Bigfish95]

A study conducted by scientists at the University of East Anglia and others at the University of Gothenburg revealed that female cichlids also have the potential to produce offspring independently. LiveScience reports that the team was surprised to find one female cichlid in their lab tanks swimming around with fertilized eggs in her mouth during the study. The tank was filled with other female cichlids, so there was no chance of the eggs being fertilized.

While the team originally assumed that this was a case of parthenogenesis being observed in female cichlids, the theory was dismissed upon closer examination of the fish. Upon looking closer at the fish’s sex organs, the subject appeared to have both normal ovaries as well as spermatocytes, cells that make sperm. This meant the fish could make offspring without the help of a mate. They named the subject “Mary.”

While under observation, Mary produced 14 broods of young and of those, 46 offspring hatched, and 17 survived. Interestingly, none of the offspring shared their mother’s unique characteristics. This observation also demonstrates how what was observed is not a case of parthenogenesis. If it had been, the offspring would have been clones of Mary, but they were not. As such, the scientist referred to the unusual reproductive ability as “selfing” instead of cloning as the spawn differed, and Mary’s offspring underwent some form of fertilization.

Conclusion​

While being able to reproduce without a mate might seem like an advantage, there are some known complications. In situations where mates are scarce, or the species is particularly isolated, the ability to reproduce independently can certainly serve its own function. However, researchers believe there are downsides to being able to self-fertilize.

Specifically, they point to a phenomenon called inbreeding depression, wherein there is such minimal genetic diversity that birth defects can occur in the generations that follow. The development of two different sexes, after all, came about very likely to ensure more diversity in genes, they say.

Researchers say that the risk of genetic defects may be why “selfing” is so exceptionally rare in nature. But they don’t rule out that it could have happened before in a lab environment—fish are rarely swimming around by themselves, they say, and scientists focusing on other questions could easily have missed them.

// I thought this was really neat and wanted to share it with you all.

Share what you think.

 

[jjohnwm]

Very interesting. I don't understand the explanation given in the link in the story, where they mention that halfclones receive half of the parent's genes while fullclones get all of them. But then they state that the fry produced by this fish are not really clones, nor are they examples of parthenogenesis, since the parent has two complete sets of reproductive organs, male and female. The eggs are fertilized more or less normally, but both sets of reproductive organs must have identical genes, no? So why do these fry not qualify as clones?

And who is the sniper?

 

[Bigfish95]

Very interesting. I don't understand the explanation given in the link in the story, where they mention that halfclones receive half of the parent's genes while fullclones get all of them. But then they state that the fry produced by this fish are not really clones, nor are they examples of parthenogenesis, since the parent has two complete sets of reproductive organs, male and female. The eggs are fertilized more or less normally, but both sets of reproductive organs must have identical genes, no? So why do these fry not qualify as clones?

And who is the sniper?

Meant to write snippet**

 

[Conchonius]

Very interesting. I don't understand the explanation given in the link in the story, where they mention that halfclones receive half of the parent's genes while fullclones get all of them. But then they state that the fry produced by this fish are not really clones, nor are they examples of parthenogenesis, since the parent has two complete sets of reproductive organs, male and female. The eggs are fertilized more or less normally, but both sets of reproductive organs must have identical genes, no? So why do these fry not qualify as clones?

And who is the sniper?

Oh, that one is easy to explain. We have two copies of each gene, called alleles, which is why we can talk about things like homozygosity, heterozygosity, and dominance. The classic example is hair color: two dark-haired parents can produce a blonde child because the dark-hair allele overrides its paler counterpart, so if both parents have one copy of each but happen to pass on the blonde allele, the kid will be blonde without any involvement from the milkman.

While producing sperm and eggs the normal way, the genome is given a little shake-up to mix the alleles, called recombination. In parthenogenesis, this either does not happen (apomixis, "away from mixing") or happens in an unusual way that can be tested (automixis, "self-mixing", which produces either almost fully homozygous or almost fully heterozygous offspring).

Test it they did, and it turned out this fish did not use parthenogenetic cloning methods with their wonky genetics. What it did was comparable to taking twin embryos, turning one of them male and one female (not that difficult with fish, as I understand it, since their sex determination partly depends on the environment), and crossing the resulting set of twins. The offspring, as a consequence, are not full-blown clones but merely the result of self-incest. All of their genes were ultimately sourced from Mary, but due to the mixing process, they got these genes in different ratios and proportions, rather than the exact same combination that would make them clones.