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Little fish makes a big splash in genomic studies; discovery may help manage an invasive species


A small fish washed up on a rocky shore. Pawel Michalak of the Virginia Bioinformatics Institute and a team of nationally recognized fishery scientists uncovered genetic factors contributing to the alewife’s ability to populate freshwater habitats.

BLACKSBURG, Va., July 14, 2014 – A little fish may once again be making a big splash, if Pawel Michalak, a researcher at Virginia Tech's Virginia Bioinformatics Institute, has anything to say about it.  

In a paper featured on the cover of the Journal of Experimental Zoology, Michalak and a team of nationally recognized fishery scientists uncovered genetic factors contributing to the alewife’s (Alosa pseudoharengus) ability to populate freshwater habitats.

The alewife in recent years made history when it invaded the Great Lakes, surmounting the natural barrier of Niagara Falls, and established a purely freshwater population. As if that weren’t enough, the fish favored as bait by lobster fishermen quickly edged out native fish and began wreaking havoc with lake trout and other native fishes.

The alewife inadvertently decimated lake trout populations because consumption of the alewife leads to thiamine deficiency complex and early mortality syndrome. Without thiamine, fish swim in spirals, are lethargic, and usually die young due to immune complications.

Now, researchers and fishery managers are trying to uncover just how the alewife has been so successful in transitioning from an anadromous lifestyle of moving between sea and freshwater to a strictly freshwater existence.  

The answer, it seems, might be within the beta-thymosin gene.

"The 'freshwater allele' of the beta-thymosin gene seems to help the alewife function in a solely freshwater environment. We also see decreased expression rates of beta-thymosin when alewives are exposed to fresh water," said Pawel Michalak, an associate professor at the Virginia Bioinformatics Institute.

Beta-thymosin has a number of functions, including building of skeletons, wound-healing, and regulating cell mechanisms. 

Understanding the genetic underpinnings of the alewife’s invasiveness is a critical stepping stone to successful management of the nuisance species, with implications for the entire Great Lakes ecosystem, including endangered native species.

The Virginia Bioinformatics Institute was established in 2000 with an emphasis on informatics of complex interacting systems scaling the microbiome to the entire globe. It helps solve challenges posed to human health, security, and sustainability. Headquartered at the Blacksburg campus, the institute occupies 154,600 square feet in research facilities, including state-of-the-art core laboratory and high-performance computing facilities, as well as research offices in the Virginia Tech Research Center in Arlington, Virginia.

Medical Informatics and Systems

The Medical Informatics and Systems research division at Virginia Bioinformatics Institute focuses on the study of human disease from an -omics analysis perspective – from clinical operations at the interface of medicine, molecular biology, and informatics to integrating and exploiting massive -omics data sets to create health information technology (Health IT) solutions.

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