With a five-year, $1.89 million grant, a UTA researcher is studying the modification of reproductive genes and how it can help with human reproductive issues such as infertility.

The grant comes from the National Institutes of Health. Biology assistant professor Sen Xu will research the reproductive genes of Daphnia, also known as water fleas.

These water fleas are small aquatic creatures and are one of the few animals that are capable of reproducing both sexually through meiosis and asexually through parthenogenesis, Xu said.

Parthenogenesis is a reproductive strategy that involves the development of a female sex cell without fertilization, according to the Encyclopaedia Britannica entry on parthenogenesis. Meiosis is the division of chromosomes that occurs during the formation of the reproductive cells of sexually reproducing organisms.

“If you can somehow tweak those genes,” Xu said, “You may be able to change the outcome completely for that meiotic division.”

Determining which genes allow the Daphnia to modify the meiosis process could help people understand the process better overall, Xu said. Meiosis is the cell division process of human reproduction.

“Even though we have some idea about how meiosis happens, there are many things we do not know in terms of the specific function of certain genes, of why something goes wrong at a certain point,” Xu said.

The National Institute of Health scores grant proposals from 90 to 10 with a lower score being better and no score being the worst. Xu’s proposal received a score of 24, which is something he said he was pleased and excited for.

“Whatever schools you can think of, they all apply to this kind of funding,” Xu said. “Only the best-scored proposals have [the] chance to receive this kind of funding.”

He said the score means his research has an impact and is highly valued by the proposal reviewers. It also means that his research now has the necessary funding to be carried out.

Xu will use gene-editing technology to determine what gene allows Daphnia to switch reproductive methods. By modifying the genes and creating hybrids he can see which ones enable the change.

The genes are edited with a process called microinjection, Xu said.

A capillary with a diameter of less than one-tenth of a hair is loaded with reagents that are injected into the embryos. The reagents diffuse into the nucleus and modify DNA sequencing, Xu said.

Xu works with several undergraduate, graduate and doctoral students on various parts of the research.

Biology seniors Dustin Luu and Hillary Vo developed an efficient method of hatching the hybrid embryos created in the lab.

When the daphnia first produce the embryos, they are in clusters that need to be dissected, Vo said.

After the embryos have been injected with the reagents, they are placed in an incubator, Xu said. They sit in total darkness for a set amount of time before being exposed to ultraviolet light, Luu said.

This method resulted in 80% to 100% hatching efficiency. After making the discovery, Luu and Vo published their findings in a peer reviewed journal called the Journal of Experimental Zoology, according to a previous Shorthorn article.

By studying the hybrids, they can observe how asexuality can come from different modes of reproduction, Luu said.

“If we gather scientific evidence and discoveries on different animals, we may gain more insight into what might be going on in humans,” Xu said.

He said the research is still in its early stages, but in a couple years he hopes to have more definitive research to present.



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