If you’ve seen The Island, you’ll have at least one idea for what a clone of yourself might be handy for. Harvesting compatible organs to replace your spent ones is a bit of a stretch from the reality, however, which is that most cloning critters simply want a simple solution for continuing on their genome. Mate selection is tiring (online dating, am I right?) and reproduction this way mixes up the gene pool, but a process called thelytokous parthenogenesis enables females to essentially print out a copy of themselves without the need for copulation.
A handy alternative, but not one without setbacks. Thelytokous parthenogenesis involves genetic recombination, which means that the babies born of it – whilst still technically clones – will be genetically different from their mothers. New research published in the journal Proceedings of the Royal Society B found that the Cape honeybee, Apis mellifera capensis, has found a way around this.
Worker Cape honeybees are churned out using thelytokous parthenogenesis, a potentially risky route of reproduction owing to the fact that if enough genetic recombination occurs, they could end up too inbred to function. This clearly hasn’t hampered the species, however, as it was found that one line of worker bees has been re-cloning since the 1990s, giving rise to hundreds of millions of cloned bees.
“The two female castes of the Cape honeybee, Apis mellifera capensis, differ in their mode of reproduction,” wrote the study authors. “While workers always reproduce thelytokously, queens always mate and reproduce sexually. For workers, it is important to reduce the frequency of recombination so as to not produce offspring that are homozygous.”
To find out how they were maintaining their genetic integrity, the researchers forced the queens – who reproduce sexually – to reproduce asexually by essentially making a bee chastity belt with a strip of surgical tape and some nail varnish. The researchers were then able to compare the asexually reproduced larvae of the queen to those of the workers.
According to a report from New Scientist, the comparison revealed that the queen’s asexually reproduced clones exhibited 100 times the amount of genetic recombination seen in the worker bees, whose larvae were near enough genetically identical to the parent. This indicates that the workers have evolved to exhibit a much lower rate of genetic recombination, most likely because it’s what works best for them.
“Evolution is just selecting what’s doing well at a given time,” said Laurent Keller at the University of Lausanne in Switzerland. “And these honeybee clones are doing quite well as they are.”
[H/T: New Scientist]
1
