From Mexico to Canberra and then Stockholm

PhD graduate Regina Trejo's research into inbreeding will continue when she takes up her postdoctoral fellowship at the University of Stockholm in August
11 July 2018

ANU PhD student Regina Trejo hopes that her ongoing research into inbreeding amongst species can help scientists discover why animals that are related are less likely to survive.

Regina, who has been studying at the Research School of Biology for the past three years, says she's interested in the inbreeding of species especially as environmental factors such as climate change continue to place pressure on species to maintain their numbers in the wild.

Regina did her undergraduate and master degrees at the University of Mexico. As part of her PhD at ANU, she has been studying the inbreeding of mosquitofish to gain a better understanding of why the survival rates of offspring between members of the same 'family' tend to be less.

"We know that mating with relatives, or inbreeding, is common in nature and it's commonly assumed that the offspring of those ones that mate with those relatives are going to be of poorer quality compared to other ones that don't mate with relatives," Regina said. "This is known as inbreeding depression.

"When they mate with relatives, these traits stay in the offspring and they are often known to be detrimental - the offspring are less likely to survive and fight diseases or predators. So that was the whole idea behind it.

"So we knew inbreeding depression was bad but then we wanted to look at the interaction between inbreeding depression and a stressful environment early in life.

"We suspected as well that if you have an individual that, early in life doesn't eat very well, their chances of survival are even less, combined with inbreeding depression."

Regina says her research found that inbreeding had no effect on how mosquitofish grew, and that the sperm traits weren't effected either. However, diet did play a role on the size of females and males, (and for males, their number and sperm quality) which therefore affected their survival rates.

"Inbreeding had no effect on their sperm traits which is maybe a bit counterintuitive. But we did do another study and because we've also inseminated some females with this sperm, it seems like when the sperm competes inside the female, that's maybe what's causing the inbreeding depression. So when inbreeding takes place, there's less chance of fertilisation."

Regina says the next stage of research in this area would be to examine what happens during fertilisation within the fish.

"I think evolutionary biology always struggles with that - we can look at it from a really broad scale and then when we try to narrow it down that's when we struggle on analysing the mechanisms."

Regina says she'll next examine the interaction between predation and cognition - how fish can think quicker for themselves for purposes such as self-defence.

She will be doing that she begins her two-year postdoctoral fellowship at the University of Stockholm in August.

Regina admits she'll be sad to leave ANU given the close-knit community of international students that have helped her make the campus home for the past few years. She says she'll also be sad to no longer be working with Professor Michael Jennions, who has been her supervisor at ANU.

"He was amazing from the start. It will be really hard to leave. I mean especially the Ecology and Evolution division is really welcoming. They're all really helpful and I think that's going to be one of the hardest things."