Genes Seem to Link Unlikely Relatives.Similarities in DNA DNA: see nucleic acid. DNA or deoxyribonucleic acid One of two types of nucleic acid (the other is RNA); a complex organic compound found in all living cells and many viruses. It is the chemical substance of genes. , the genetic material that's passed along from an animal to its offspring, can be a strong indicator of kinship. After all, even if you didn't get your father's nose, you got a hefty dose of his DNA. Using that line of reasoning Noun 1. line of reasoning - a course of reasoning aimed at demonstrating a truth or falsehood; the methodical process of logical reasoning; "I can't follow your line of reasoning" logical argument, argumentation, argument, line , an international team of scientists contends that markers in the genes of three proteins suggest a single African ancestor for animals as diverse as elephants and aardvarks. The researchers, led by scientists at the University of Nijmegen (body, education) University of Nijmegen - Katholieke University of Nijmegen (KUN), Nijmegen, the Netherlands. KUN's Computing Science Institute. is known for the Clean, Comma, Communicating Functional Processes, and GLASS projects. http://kun.nl/. in the Netherlands, present their findings in the Jan. 2 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES The Proceedings of the National Academy of Sciences of the United States of America, usually referred to as PNAS, is the official journal of the United States National Academy of Sciences. . Almost a third of the major groupings, or orders, of mammals actually can be lumped into a superorder su·per·or·der n. A taxonomic category of related organisms ranking below a class or subclass and above an order. superorder called Afrotheria, says Wilfried W. de Jong De Jong is the most common Dutch surname. Many people bear this name, including many important historical figures. Some of these people are mentioned below. De Jong may mean:
"This is an odd collection of mammals, and it's tough to convince biologists who depend on morphology that this is a valid grouping," admits S. Blair Hedges. An evolutionary biologist at Pennsylvania State University Pennsylvania State University, main campus at University Park, State College; land-grant and state supported; coeducational; chartered 1855, opened 1859 as Farmers' High School. in University Park, he says in the same issue of the journal that the genetic similarities can best be explained by a common ancestor. Morphologists, who seek biological relationships among organisms, typically look for common traits such as feathers or fur to discern kinship, says Hedges. In this particular case, he notes, the researchers have applied the morphologists' rules of classification to genetic instead of structural markers. "One hopes that molecules and morphology would tell the same story," says de Jong. But when the two differ, he contends, genetic markers are simpler to interpret. It's always possible that convergent evolution convergent evolution n. See convergence. could cause a particular physical feature to evolve, de Jong notes. However, he says, he can't imagine a biological mechanism that could randomly cause matches in markers on the genes for three different proteins in the Afrotherians. According to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. the team's statistical analyses, the probability of such an event is negligible. Over the past 3 years, studies of genetic material by de Jong and his colleagues have indicated that Afrotherians are descended from a species that probably lived about 100 million years ago. This common ancestor evolved in an Africa isolated after it split from South America but before the continent drifted eastward to join Eurasia and was likely a small forest dweller that ate insects, Hedges says. Although there are no physical characteristics that distinguish the animals linked by the genetic analysis, Hedges says, the combination of the molecular evidence, the geographic distribution of the animals today, and the geologic history of the African continent provides convincing support for their kinship. |
|
||||||||||||||||||||

Printer friendly
Cite/link
Email
Feedback
Reader Opinion