Posts Tagged ‘genetics’

Polygamy is the key to a sweeter life

 :: Posted by American Biotechnologist on 06-18-2013

Image credit: David Tarpy

When it comes to honey bees, more mates is better. A new study from North Carolina State University, the University of Maryland and the U.S. Department of Agriculture (USDA) shows that genetic diversity is key to survival in honey bee colonies – a colony is less likely to survive if its queen has had a limited number of mates.

“We wanted to determine whether a colony’s genetic diversity has an impact on its survival, and what that impact may be,” says Dr. David Tarpy, an associate professor of entomology at North Carolina State University and lead author of a paper describing the study. “We knew genetic diversity affected survival under controlled conditions, but wanted to see if it held true in the real world. And, if so, how much diversity is needed to significantly improve a colony’s odds of surviving.”

Tarpy took genetic samples from 80 commercial colonies of honey bees (Apis mellifera) in the eastern United States to assess each colony’s genetic diversity, which reflects the number of males a colony’s queen has mated with. The more mates a queen has had, the higher the genetic diversity in the colony. The researchers then tracked the health of the colonies on an almost monthly basis over the course of 10 months – which is a full working “season” for commercial bee colonies.

The researchers found that colonies where the queen had mated at least seven times were 2.86 times more likely to survive the 10-month working season. Specifically, 48 percent of colonies with queens who had mated at least seven times were still alive at the end of the season. Only 17 percent of the less genetically diverse colonies survived. “48 percent survival is still an alarmingly low survival rate, but it’s far better than 17 percent,” Tarpy says.

“This study confirms that genetic diversity is enormously important in honey bee populations,” Tarpy says. “And it also offers some guidance to beekeepers about breeding strategies that will help their colonies survive.”

The paper, “Genetic diversity affects colony survivorship in commercial honey bee colonies,” was published online this month in the journal Naturwissenschaften. Co-authors of the study are Dr. Dennis vanEngelsdorp of the University of Maryland and Dr. Jeffery Pettis of USDA. The work was supported by the USDA Cooperative State Research, Education and
Extension Service, the USDA Agricultural Research Service, the North Carolina Department of Agriculture and Consumer Services and the National Honey Board.

Thanks to NC State University for this story.

The Ghost in Your Genes

 :: Posted by American Biotechnologist on 05-13-2013

Where liberal arts meets biology

 :: Posted by American Biotechnologist on 12-05-2012

Students are often faced with with some very contradictory decisions. Liberal arts or natural sciences? English literature or chemistry? The classical educational framework forces students to choose early on which path they will take and, as a result, students with a penchant for history will rarely be exposed to the intricacies of biology. However, a new study out of Columbia University’s School of Engineering and Applied Sciences, may give those who are ready to trade-in their biology textbooks for lessons in history a reason for second-thought.

In a study published in the November 2012 issue of The American Journal of Human Genetics (AJHG), Columbia scientists describe a new approach used to analyze genetic data to learn more about the history of populations. The authors are the first to develop a method that can describe in detail events in recent history, over the past 2,000 years. They demonstrate this method in two populations, the Ashkenazi Jews and the Masai people of Kenya, who represent two kinds of histories and relationships with neighboring populations: one that remained isolated from surrounding groups, and one that grew from frequent cross-migration across nearby villages.

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Rewriting Molecular Biology Textbooks…Again!

 :: Posted by American Biotechnologist on 05-17-2012

Over the past decade, research in the field of epigenetics has revealed that chemically modified bases are abundant components of the human genome and has forced us to abandon the notion we’ve had since high school genetics that DNA consists of only four bases.

Now, researchers at Weill Cornell Medical College have made a discovery that once again forces us to rewrite our textbooks. This time, however, the findings pertain to RNA, which like DNA carries information about our genes and how they are expressed. The researchers have identified a novel base modification in RNA which they say will revolutionize our understanding of gene expression.

Their report, published May 17 in the journal Cell, shows that messenger RNA (mRNA), long thought to be a simple blueprint for protein production, is often chemically modified by addition of a methyl group to one of its bases, adenine. Although mRNA was thought to contain only four nucleobases, their discovery shows that a fifth base, N6-methyladenosine (m6A), pervades the transcriptome. The researchers found that up to 20 percent of human mRNA is routinely methylated. Over 5,000 different mRNA molecules contain m6A, which means that this modification is likely to have widespread effects on how genes are expressed.

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What do you get when you cross yeast and first year biology students?

 :: Posted by American Biotechnologist on 05-01-2012

What do you get when you cross a yeast and first year biology students?

Apparently, a very cool undergraduate course and significant scientific innovation!

UC Berkeley students who are lucky enough to be enrolled in the university’s entry-level biology course are being exposed to a discovery-based learning curriculum that gives them hands-on bench experience and has resulted in the discovery of a novel technique published in the current issue of Genetics.

Under the mentorship of University of Massachusetts Amherst geneticist Jacob Mayfield, students devised a technique for testing the consequence of variant human gene alleles by moving them into yeast cells. Once swapped into yeast, colony growth was be compared to reveal functional differences.

The technique was used to compare allelic differences in the Cystathionine-beta-synthase (CBS) gene, created by site-directed mutagenesis. Deficiencies in the gene causes homocystinuria which can be rescued by vitamin B6 treatments. However, only some individuals respond to vitamin B6 treatment while others do not. Using the yeast metabolic profiling technique, researchers were able to ascertain which individuals, (based on their CBS sequence), would respond to the B6 treatment and which would not.

Sounds like a winning program to me!

Citation: Mayfield JA, Davies MW, Dimster-Denk D, Pleskac N, McCarthy S, Boydston EA, Fink L, Lin XX, Narain AS, Meighan M, & Rine J (2012). Surrogate genetics and metabolic profiling for characterization of human disease alleles. Genetics, 190 (4), 1309-23 PMID: 22267502

Source: UMass