Environmental Factor – August 2020: Distinguished Lecture Exploring Social Genetic Influences in Fish

Ewan Birney, Ph.D., on July 21, titled “Using Genetics to Understand the Environment: A Story of Fish and Humans” as part of the distinguished NIEHS Lecture Series. He is Deputy Director General of the European Molecular Biology Laboratory (EMBL) and Director of the EMBL European Bioinformatics Institute (EBI). Kimberly McAllister, director of health scientist at the National Institute for Health and Safety, hosted this virtual event.

The study of sociogenetic influences also included chickens, pigs and mice, Bernie said. (Photo courtesy of Carrie Tang)

Birney received a NIEHS grant in 2019 to study how environmental chemicals affect Japanese rice fish, also known as medaka fish. With this project still in its infancy, he instead spoke of another of his studies in a field called sociogenetic influences, which studies the ways in which genetic diversity can alter animals’ behavior when they are around others.

A tried and true model

Scientists first used medaka as a model to study genes more than 100 years ago, according to Bernie. Like other model organisms used in research, such as the fruit fly and the plant Arabidopsis thalianamedaka fish can reproduce from the wild and become homozygous, which means they have two copies of the same variations, or alleles, of a particular gene.

Collaboration with scholars like Kiyoshi Narus, Ph.D., at the National Institute of Basic Biology in Okazaki, Japan, and Jochen Wittbrot, Ph.D., and Felix Losley, Ph.D., at the University of Heidelberg in Germany, Bernie was the first to create a fungal line of medaka fish. He and his colleagues currently own 80 strains of medaka fish, each with its own genetic signature. Only female fish are used in experiments (see second sidebar).

frightened and antisocial

Medaka fish strains were tested using eight tanks. Four features a female from the Medaka line called Max, paired with a fish from a reference line called the iCab. All fish in this reference line are genetically the same. The other four tanks contained a female Medaka named David and a fish from the iCab line. The water in each four-pond setup was separated by a partition, so pairs of fish couldn’t see other pairs. The computer tracks the movements of each fish.

The research team noticed that Max’s fish and iCab were actively exploring their ponds, but David’s fish were still static.

This image shows the Max fish actively moving around in green, on the left, compared to David’s fish still circled in red, on the right. The other fish is the iCab. (Photo courtesy of Ewan Bernie)

“David’s fish are alive and will mate, but in this place, they are fossilized and still,” said Bernie. David and Max created an environment for the other [iCab] Fish, but it’s not a physical or chemical environment – it’s a social environment.”

The glamorous medaka

This socialization can be seen when Bernie compares David Fish with another Medaka line called Elsa. The female fish of this line also remained frozen, but surprisingly they convinced their iCab partners to follow their lead and remain relatively still.

According to Bernie, David and Elsa Fish created their own social environment, with Elsa being charismatic and David even less so. Bernie’s team is looking to go beyond these extremes — say, a boring line with a charismatic line — to map genetics and understand how these social environments are created.

“Bernie’s work with medaka demonstrates the advantages of this system for studying socio-environmental factors and how this resource can be used in other environmental health research as well,” McAllister said.

from San Jose News Bulletin https://sjnewsbulletin.com/environmental-factor-august-2020-distinguished-lecture-exploring-social-genetic-influences-in-fish/