One of the few mammals that lays eggs offers clues to evolution of all mammalian genes
WEDNESDAY, May 7 (HealthDay News) -- An international team of scientists has published the first analysis of the genome sequence of the duck-billed platypus, one of the few mammals that lays eggs.
The research offers clues about how genomes were organized during the early evolution of mammals.
"At first glance, the platypus appears as if it was the result of an evolutionary accident. But as weird as this animal looks, its genome sequence is priceless for understanding how fundamental mammalian biological processes have evolved. Comparisons of the platypus genome to those of other mammals will provide new insights into the history, structure and function of our own genome," Francis S. Collins, director of the U.S. National Human Genome Research Institute (NHGRI), said in a prepared statement.
The NHGRI helped fund the analysis of the genome sequence of the platypus, which is native to Australia and has many unique characteristics. Along with being one of the few mammals that lays eggs, the platypus has a duck-like bill, an electrosensory system it uses to forage for food underwater, and a thick fur coat adapted for icy waters. Males have hind leg spurs that can deliver venom that causes excruciating pain.
The researchers found that the platypus genome contains about the same number of protein-coding genes as other mammals (approximately 18,500) and also shares more than 80 percent of its genes with other mammals whose genomes have been sequenced.
The scientists then looked for unique parts of the platypus genome that have been lost from mammalian genomes, as well as genetic features associated with reptiles.
"The mix of reptilian, mammalian, and unique characteristics of the platypus genome provides many clues to the function and evolution of all mammalian genomes," study senior author Richard K. Wilson, director of Washington University School of Medicine's Genome Sequencing Center, said in a prepared statement. "Now, we'll be able to pinpoint genes that have been conserved throughout evolution, as well as those that have been lost or gained."
The research was published in the May 8 issue of the journal Nature.
"This genome provides a unique perspective on what the genomes of our earliest mammalian ancestors may have looked like. It is fascinating that what we think of as being reptile-like (i.e., egg laying and venom) and mammal-like features can co-exist in the same genome," Adam Felsenfeld, head of the Comparative and Sequencing Analysis Program in NHGRI's Division of Extramural Research, said in a prepared statement.
The NHGRI has more about genomics.
-- Robert Preidt
SOURCE: U.S. National Human Genome Research Institute, news release, May 7, 2008
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