Avian genome analysis covers nearly all hen households

Scientists are well on their way to capturing a full genetic portrait of the diversity of the world's birds.

In the November 11th issue of Nature, researchers reported the genome of 363 species of birds, including 267 that were sequenced for the first time. The species studied represent more than 92 percent of the world's bird families. The data from the study will fuel bird development research and support the conservation of threatened bird species.

"It may seem like a genome for each bird family or species is a bit like stamp collecting, but this massive collaboration has given us a number of very important genomic resources for conservation," said Rob Fleischer, one of the authors and directors of the Center for Conservation Genomics at the Smithsonian Conservation Biology Institute. “For example, it provides a simple source of genetic markers that are useful for mapping population declines, identifying relatives, and reducing inbreeding when managing rescue populations of endangered species. The presence of the genomes makes it easier to find genes that are responsible for important survival traits such as resistance to fatally introduced diseases. "

Together, the data form a rich genomic resource that is now freely available to the scientific community. The publication of the new genomes marks a major milestone for the Bird 10,000 Genomes Project (B10K), an international collaboration organized by researchers at 10 institutions, including the Smithsonian National Museum of Natural History. The aim is to sequence and share the genome of every species of bird on the planet.

The B10K project works in four phases. The first phase, which was completed a few years ago, dealt with bird orders. The second phase that this new article is about is family level analysis. The process is currently underway for phase three – the genus level analysis. Then four individual species are examined in phase.

What genes say about species divisions

Approximately 40% of the newly sequenced avian genomes were obtained from tissue samples held in the National Museum of Natural History's Avian Genetic Resource Collection, begun in 1986, and have since been part of the Smithsonian's Global Genome Initiative biorepository. Photo by Chip Clark / Smithsonian

We asked Fleischer if the work would help decide whether certain similar bird species or populations – for example, northern cardinals in the southwest and east – could be grouped or divided based on genetics.

"The analysis in this particular article focuses primarily on one species from each bird family, so the issue of taxonomy at the species level is not addressed directly," he explains. “However, genome sequences from several individuals and regions within a species or genus offer us the opportunity to assess genetic differences between regional populations, subspecies and suspected species. If the genomic sequences show very little gene flow or very little hybridization between these subunits (e.g. the example of cardinals in the Southwest isolated from those in the eastern US), we can say that their existence as distinct units supports and possibly divides you. (But differences other than genomic usually also need to be considered to determine whether the differences imply a species-level division.)

“And the resources that we get from complete genome sequences from a wide range of species across the avian class allow us to develop a large number of genetic markers that we can use in place of genomes to answer these taxonomic questions. The markers developed from one species are often effective in related species of the same genus or family. However, it is becoming easier and cheaper to sequence entire genomes of individual birds, so the use of such markers could soon come to an end.

“And the ultimate goal of the B10k project is to sequence all> 10,000 bird species. Hence, at this point it should not be necessary to apply what we learn from a species to develop markers for studying related species.

"Answering questions about taxonomy and" units of evolutionary importance "can be important in determining units for conservation policy and measures and ultimately contributing to the conservation of bird diversity."

A version of this article will be published in the January / February 2021 issue of BirdWatching magazine.

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