July 18 () –
Hundreds of millions of years ago, microbes and plants might have provided insects with a evolutionary advantage by transmitting genes to them by horizontal transferaccording to a study published in the journal ‘Cell’ where researchers report that more than 1,400 genes from 218 insect speciesincluding butterflies and moths, originated from bacteria, viruses, fungi, and plants.
The study argues that these genes could have been essential to the evolution of insects by allowing them to develop beneficial traits in mating behavior, nutrition, growth, and adaptation to environmental changes.
Horizontal gene transfer (HGT) is quite common among microbes. For example, bacteria use this mechanism to transmit antibiotic resistance genes between species, but more recently scientists have systematically studied the phenomenon between insects and microbes or plants.
“Previous studies have shown that THG may have contributed to insect biodiversity, but no one knew how important it is in this process, says lead author Xing-Xing Shen, an evolutionary biologist at Zhejiang University in Hangzhou, China. Since there are many high-quality insect genomes available for our analysis, I thought now is a good time to systematically investigate the prevalence of THG in insects.”
Shen’s team began this project in collaboration with Antonis Rokas, an evolutionary biologist at Vanderbilt University in the United States, by assembling 218 high-quality insect genome samples representing 11 of the 19 species-rich insect orders. With the data, they were able to draw an evolutionary tree, identify the misplaced genes most commonly found in non-animal genomes, and examine what factors contribute to the fate of THG in insects.
“There were THG events everywhere we looked Shen says. However, we do not know whether these gene transfers are beneficial to the insects, or including the functions of most of these genesTo do this, he enlisted the help of another expert, Jianhua Huang, who studies the functions of insect genes at Zhejiang University.
“Shen walked into my office with a list of over 1,400 genes and we had to decide where to start.Huang recalls. The team decided to validate the function of the most frequent foreign gene with no known functions in insects: LOC105383139.
“This gene was introduced horizontally into almost all moths and butterflies from a donor of the bacterial genus Listeria“, they report in the study, which means that this gene has persisted in the genome since the time of the common ancestor of moths and butterflies, more than 300 million years ago.
They decided to remove this ancient gene from diamondback moths, a pest that affects broccoli and cabbage, and see what kind of functions it has. “Surprisingly, we saw that moths that lack this gene can’t produce many viable eggs, Huang said. We then found that the gene influences the courtship behavior of males.”
The group plans to further investigate the mechanisms that explain how this gene helps insects mate more efficiently and whether it can be used as a pest control tool.
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