(Photo credit: Mainstream Aquaculture
)
Barramundi farmers will soon be able to improve stock genetics by placing more emphasis on the sex of their breeding fish.
University of Queensland PhD candidate Jessica Hintzsche has produced the most detailed genetic map ever created for barramundi showing how traits can be passed between generations.
“It gives us the ability to be more targeted in breeding and choose the sex that gives the best chance of keeping good traits like more robust growth and disease resistance, and separating them from less desirable traits,” Ms Hintzsche said.
“It’s also a step beyond genomic selection, allowing us to speed up genetic improvement but still conserve diversity in breeding populations by focusing on the chromosome chunks created by recombination.
“By focusing on how these chunks are inherited, we can make smarter breeding decisions without narrowing the gene pool.”
Jessica Hintzsche produced the most detailed genetic map ever created for barramundi.
(Photo credit: QAAFI)
The research at the Queensland Alliance for Agriculture and Food Innovation (QAAFI) revealed a rare genetic pattern in barramundi where males and females reshuffle DNA during reproduction in completely different parts of their chromosomes, with no overlap between the sexes.
This contrasts with other species, where the reshuffling is spread more evenly across the chromosome and differs only slightly between males and females.
This reshuffling process, known as recombination, is essential for generating genetic diversity.
“In Australian barramundi, females only recombine near the chromosome centromere, while males recombine exclusively at the chromosome ends,” Ms Hintzsche said.
“This finding is incredibly exciting because it’s so rare and completely changes how we think about breeding for the species.
“Barramundi are unique and can change sex during their lifetime, which means breeders can influence whether a fish becomes male or female and which parts of its genome are passed on.”
The linkage maps, including male and female specific and consensus versions, have been published and will provide a valuable resource for researchers and breeders.
The linkage maps will provide a valuable resource for commercial fish breeders.
(Photo credit: Mainstream Aquaculture)
Ms Hintzsche said the work laid the groundwork for advanced breeding approaches as well as those who are interested in understanding the evolution of recombination.
“This isn’t just about barramundi, it challenges long held assumptions in genetics and shows what’s possible when we invest in understanding a species properly, especially at a genetic level,” she said.
The research was published in Aquaculture.
Collaboration and acknowledgements
The Australian Research Council Research Hub for Supercharging Tropical Aquaculture through Genetic Solutions is led by James Cook University with funding from the Department of Primary Industries, Mainstream Aquaculture Group, The Company One, Cygnet Bay Pearls, Australian Genome Research Facility, and The University of Queensland.
The Queensland Alliance for Agriculture and Food Innovation is a research institute at The University of Queensland, established with and supported by the Department of Primary Industries.
