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Elaina Tuttle, 1963 - 2016


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#1 Ellen Paul

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Posted 16 June 2016 - 02:53 PM

Elaina M. Tuttle, Ph.D., a professor at Indiana State University who was known for her long-term studies on White-throated Sparrows and Fairy-wrens passed away on 15 June 2016. Over her career, she examined how ecology, behavior, genetics, and physiology maintain natural variation through their influence on the evolution of life-history strategies, phenotypic expression, and both the relative fitness and frequency of genotypes within a population. Dr. Tuttle wasinvolved in two projects that investigate these factors: 1) a study of the maintenance of polymorphism via disassortative mating in the white-throated sparrow (Zonotrichia albicollis), and 2) a study of sexual selection and the evolution of mating systems in Australian fairy-wrens (Malurus splendens, M. lamberti, M. leucopterus) in collaboration with Stephen Pruett-Jones (University of Chicago) and Michael S. Webster (Washington State University).

 

Dr. Tuttle, who earned her doctorate at SUNY Albany, utilized observational and experimental methods in the field and laboratory, molecular genetic techniques (e.g. minisatellite DNA fingerprinting, microsatellites, RAPDs, AFLPs), physiological techniques (e.g. semen sampling, hormonal analyses, and immunological analyses), and other multi-disciplinary techniques (e.g. karyotyping, histology). An integrative approach often reveals new alternative hypotheses and allowed her to investigate evolutionary questions at proximate and ultimate levels. Dr. Tuttle had a general interest in population genetics, the nature and organization of genetic variation in populations, and how genetic diversity affects the conservation of species. She collaborated on several such research projects on a variety of organisms ranging from mammals to insects.

 

Earlier this year, Dr. Tuttle published a paper in Current Biology reporting on the achievements of her 27-year collaboration with Rusty Gonser (her husband, also Indiana State University) into white-throated sparrows at Cranberry Lake in New York. Their efforts have led to greater understanding of the birds' supergene, its apparent degradation and the species' evolution. She called it her pinnacle paper and said that "I think of all the researchers throughout the years, all the field assistants and graduate assistants who have been collaborators. It's nice because even though they may not be in authorship, a little part of them is in there." She added: "Typically, researchers have genomics data or they have field data. "You don't often have both integrated into a nice story together."

 

And that field data dates back nearly three decades.

"We can go back in history and do the genomics from samples from 1988 and see how genes change over time. It's a really rich database," she said.

Until genome sequencing capabilities caught up with Tuttle, she says it was like having a black box that needed to be unlocked.

"I knew there were secrets in there, and we're just beginning to see," she said. "Now, the data can be mined by us and other researchers because it's on a public database."

As questions are answered, even more are asked.

"I'm excited. There's so many other things we can find out—how genes arise, how they're maintained, how they work," she said. "We're even thinking about doing epigenetics, which is how genes are turned on or off. One of the future projects we're looking at is how stress turns on certain genes. That's a big thing in human disease, as well. Stress turns on certain genes that cause disease later in life. It's a good model for human behavior as well."

Read more at: http://phys.org/news...lution.html#jCp

 

Elaina M. Tuttle et al. Divergence and Functional Degradation of a Sex Chromosome-like Supergene, Current Biology (2016). DOI: 10.1016/j.cub.2015.11.069 

Read more at: http://phys.org/news...lution.html#jCp

 

 

Dr. Tuttle was a member of the American Ornithologists' Union and the Wilson Ornithological Society. 


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#2 Ellen Paul

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Posted 21 March 2017 - 12:30 PM

A wonderful article in Nature, Nov. 2016, about Elaina Tuttle's work. 

 

The sparrow with four sexes

Elaina Tuttle spent her life trying to understand the bizarre chromosome evolution of a common bird — until tragedy struck.

 

"Her entire career, and most of Gonser's, had been devoted to understanding every aspect of the biology of the white-throated sparrow (Zonotrichia albicollis). Less than six months before she died this year at the age of 52, the couple and their team published a paper1 that was the culmination of that work. It explained how a chance genetic mutation had put the species on an extraordinary evolutionary path.

The mutation had flipped a large section of chromosome 2, leaving it unable to pair up with a partner and exchange genetic information. The more than 1,100 genes in the inversion were inherited together as part of a massive 'supergene' and eventually drove the evolution of two different 'morphs' — subtypes of the bird that are coloured differently, behave differently and mate only with the opposite morph. Tuttle and Gonser's leap was to show that this process is nearly identical to the early evolution of certain sex chromosomes, including the human X and Y. The researchers realized that they were effectively watching the bird evolve two sex chromosomes, on top of the two it already had.

“This bird acts like it has four sexes,” says Christopher Balakrishnan, an evolutionary biologist at East Carolina University in Greenville, North Carolina, who worked with Tuttle and Gonser. “One individual can only mate with one-quarter of the population. There are very few sexual systems with more than two sexes.”






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