Male crazy ants have two different sets of DNA in their bodies.

Most male yellow loopy ants carry two separate units of DNA originating from sperm and egg cells that don’t combine their genetic materials after fertilization.

Which means males are chimeras – people who carry one set of genes in some components of the physique and one other in different components. Male offspring develop as both staff or queens, relying on the DNA within the sperm cell that fuses with the egg, whereas the grandchildren themselves develop into chimeras.

The findings, fixing a 15-year-old thriller in regards to the beetle’s genetics, reveal a type of replica hitherto “unknown to science”. Hugo Darras on the Johannes Gutenberg College Mainz in Germany.

“There have been plenty of loopy hypotheses explaining what was happening with these ants, however none as loopy as we found,” he says.

Ants typically reproduce both by sexual replica (a male’s sperm fertilizes a feminine’s egg) or by clonal replica, which means the queen produces offspring with out the added genes of a second guardian. Usually, males originate from unfertilized eggs and females originate from fertilized eggs. Normally, queens are genetically just like staff in the identical colony, however on account of particular care and feeding they develop into queens.

In 2007, scientists studied the genomes of yellow loopy ants (Anoplolepis gracilipes) and located, to their shock, that men had mixed genetics as if they had two parents. Six years later, one other group found that each one queens in a colony got here from the identical genetic line, and The worker sisters were all of a very different, second ancestry..

Intrigued by this puzzle, Darras and his colleagues sequenced the DNA of 53 yellow mad ant queens and 91 staff collected from 14 places in Southeast Asia. Queens interbred, however staff had a lot increased genetic variety, he says. In different phrases, queens seemed to be born from dad and mom of the identical ancestry, and staff from dad and mom of various ancestry – despite the fact that the males who fathered all of them got here from the identical colony.

Assuming this meant that the colonies contained two male lineages, the researchers then collected 574 males with queens and staff from the identical colonies and sequenced the DNA of their legs. They discovered that a number of the males appeared to share a genetic line with the queens, whereas others seemed to be extra carefully associated to the employees.

This may make sense if males had been descended from fertilized eggs, Darras mentioned, as a result of that may imply that they had two copies of every chromosome—one from every guardian. However his group’s evaluation revealed that, like most ants, bees, and wasp males, they’ve just one copy of every chromosome and due to this fact descend from unfertilized eggs.

The group then examined DNA from particular person cells in 20 males. They found that roughly half of the cells in the identical particular person insect had genes from one lineage and the opposite half had genes from the opposite lineage. Wanting particularly at sperm cells, the group discovered that one lineage that gave rise to staff far outnumbered the opposite.

Additional evaluation revealed that the 2 progeny in these males descended from two dad and mom, which means that the males truly got here from fertilized eggs, however not like the females, the nucleus of the egg didn’t fuse with the nucleus of the sperm. So males obtained two completely different units of chromosomes that had been moved to completely different components of the physique.

On reflection, researchers realized that the overwhelming majority of yellow mad male ants had been possible chimeras, and DNA samples from the legs of bugs solely confirmed the genetic materials of that leg, Darras mentioned.

The ants might have developed such a peculiar reproductive system due to an historic battle between lineages, he says. Particularly, if the worker-producing progeny at all times creates sterile females when the egg and sperm mix, then if it might probably slip inside an egg with out fusing it might probably guarantee its survival for generations. It then turns into the first DNA sequence within the sperm of fertile males, making it a “egocentric” lineage.

“That is simply hypothesis,” Darras says. “We’re simply in the beginning of our understanding.”