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Monday, October 29, 2012 BGSU
BGSU Zoom News

Alumna Gabrielle Knafler with Juan Bouzat and undergraduate Tyler Sojka at a research presentation
Alumna Gabrielle Knafler (left) with Juan Bouzat (right) and undergraduate Tyler Sojka at a research presentation.

For penguins, choosing the right mate is key

When it comes to disease resistance, evolution may favor choosing specific mates or selecting resistant individuals for survival and reproduction. A study by BGSU biologist Dr. Juan L. Bouzat and former biological sciences master's student Gabrielle Knafler finds that disease resistance in South America's Magellanic penguins has evolved through natural selection for genetically variable individuals. The work was recently published in the Journal of Heredity, and will be featured on the cover of the December 2012 issue.

The conservation genetics study is timely because even though their individual colonies often still number in the millions, as a whole the Magellanic species seems to be dwindling, and has been classified as Near Vulnerable by the International Union for Conservation of Nature and Natural Resources.

Magellanic penguins, which are found exclusively south of the equator, have a high level of variation in genes associated with the ability of birds and mammals to fight infectious disease, but Bouzat and Knafler reported that the mechanism the penguins use to ensure that diversity is "far from black and white."

Diversity in genes between members of mating pairs is important for providing the range of disease resistance and hardiness needed to perpetuate the species. The first stage of the study found that, compared to other penguin species, Magellanic penguins seem to have more diversity in terms of the Major Histocompatibility Complex (MHC) - a gene family that controls the interaction between white blood cells and infectious agents. Penguins, like humans, inherit two sets of genes for every trait - one from each parent - and for survival's sake it is more beneficial that genes at the MHC have unmatched pairs (heterozygosity).

But how do the Magellanic penguins maintain this strong genetic diversity? Is it through choosing mates with different MHC genes (disassortative mating), or is it through natural selection favoring the survival and reproduction of individuals with diverse MHC genes? Bouzat said that in some species, individuals choose their mates based on their different MCH genes. "In some of these species, individuals discriminate among potential mates by MHC type on the basis of olfactory cues," he said.

Working in Bouzat's lab at BGSU, Knafler looked at 50 pairs of breeding penguins to see if MHC diversity was greater than in random pairs and whether their MHC genotypes correlated with their fitness, as measured by the number of eggs hatched and chicks fledged. Although she and Bouzat did not find significant evidence that the penguins chose mates based on their having a different genotype from their own, they did find a direct connection between heterozygosity (or diverse genes) and superior fitness of adults.

The heterozygous females (those with unmatched pairs of genes) hatched significantly more eggs and fledged significantly more chicks than homozygous females (in fact, none of the females with matching pairs of genes who hatched eggs actually fledged any chicks), the study reports. This finding suggests that a natural selection for disease resistance, rather than mate choice, is at work in maintaining MHC diversity in the Magellanic penguin.

Additionally, they found through studying an evolutionary "family tree" of the MHC genes from other penguin species that the origin of some gene variants pre-dated the actual diversification of penguin species.

"The direct association of MHC genes with mechanisms of disease resistance and fitness and the evolutionary signals in their DNA sequences suggest that the maintenance of MHC diversity could be driven by periodic selection due to different pathogens, similar to epidemics in humans," Bouzat said.

The study represents one of the few examples providing direct evidence for the role of natural selection in the evolution of disease resistance in a wildlife species.

 


BGSU
in the news

Miller on the Battle for Ohio
- The Guardian UK

BGSU campaign volunteer featured
- The Guardian UK

BGSU collects, recycles sneakers
- Sentinel–Tribune

Northwest Ohio's presidential importance
- Fremont News-Messenger


ZOMBIES!
BGSU zombie Chad Hensley (standing, center) and alumni zombie Anna Gorman '12 (right) attack Andrew Pate (center) while Zombie Patrol member Nat Gotro (left) fights off his zombie classmates.

Zombies sighted in downtown Bowling Green

It was "Night of the Living Dead" in Bowling Green Oct. 17, when even the public library seemed to be taken over by zombies.

A number of the creepy creatures on the "Zombie Walk" were students from the University, out for an evening of fun among the humans. They could be seen having their picture taken at Grumpy Dave's Pub along with characters from the "Haunted Hydro" Halloween funhouse, snacking on zombie treats at Grounds for Thought, perfecting their Zombie good looks at Serenity Spa and competing in the Rot or Not contest. Keeping an eye on things was the Zombie Patrol.

Luckily for the town's inhabitants, the zombies were friendly and out for a good cause. The Zombie Walk for Charity supported local nonprofit Computers for Charity and Bowling Green Teen Central and collected food items for Bowling Green Christian Food Pantry.

The event was a perfect match for the BGSU Office of Service-Learning (OSL), which helped recruit zombie participants and volunteers. "We also coordinated the volunteer management, which included training and supervising volunteers in a variety of roles: makeup artists, check-in, and downtown information posts," said OSL major-event coordinator Paul Valdez.

The office has had a long affiliation with BG Teen Central, he added, and it was eager to help cultivate a developing nonprofit, Computers for Charity. "The event was a great opportunity for us to provide assistance of capacity building for both organizations, and it fit within the scope of our mission as an office," Valdez said.

About 35 BGSU students participated as volunteers, in addition to those who came as zombies. "In my eyes it was a great way for permanent residents and BGSU students to interact," Valdez said.

These included BGSU student Briee Neil, a theater and film major who put her skills to work "zombifying" the participants, and Nat Gotro, who served on the Zombie Patrol.

'Second Honeymoon' and 'Jurassic Babies' in brief

Dr. Kristen Rudisill, popular culture, will share her research into Tamil-language Indian popular theater in a talk tomorrow. Find out more In Brief.

 

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October 29, 2012