Evolution

In the current issue of Science, researchers from the European Molecular Biology Laboratory's European Bioinformatics Institute [EMBL-EBI] uncover systematic errors in existing methods that compare genetic sequences of different species to learn about their evolutionary relationships. They present a new computational tool that avoids these errors and provides accurate insights into the evolution of DNA and protein sequences. The results challenge our understanding of how evolution happens and suggest that sequence turnover is much more common than assumed. The four letter code that…

The newly sequenced genome of a dainty, quill-like sea creature called a lancelet provides the best evidence yet that vertebrates evolved over the past 550 million years through a four-fold duplication of the genes of more primitive ancestors. The late geneticist Susumu Ohno argued in 1970 that gene duplication was the most important force in the evolution of higher organisms, and Ohno's theory was the basis for original estimates that the human genome must contain up to 100,000 distinct genes. Instead, the Human Genome Project found that humans today have only 20,000 to 25,000 genes, which…

Male homosexuality is difficult to explain under strictly Darwinian evolutionary models, because carriers of genes predisposing towards male homosexuality would be likely to reproduce less than average, suggesting that alleles influencing homosexuality should progressively disappear from a population. Partly due to that, homosexuality in males is thought to have both psycho-social factors and genetic components. This is suggested by the high concordance of sexual orientation in identical twins and the fact that homosexuality is more common in males belonging to the maternal line of male…

The Y chromosome is an established evolutionary tool and has been used in many evolutionary studies. While easy to use, it has limitations which prevent it from full utilization about the most evolutionary informative DNA segments in the Human genome. As part of her doctoral studies, Holly Leung in the Department of Genetics at University of Leicesteris has been investigating the potential of the X chromosome as another evolutionary informative segment in the human genome. The University of Leicester has done many human population studies with the Y chromosome, including the relationship…

I've written this post to address some of the issues raised in the comments to my first post on the evolution versus creationism debate.   (1) A major reason that Biblical creationism thrives in certain parts of America is because -- unlike every other highly developed country in the world -- we do not have a national science curriculum.  America has a very strong tradition of "home rule" which means that state and local school boards can choose, if they wish, to exclude any discussion of evolutionary mechanisms in biology classes.  (I was elected to my own local school…

In May, Nature magazine published a draft sequence of the entire genome of the platypus, the bizarre mammal endemic of Australia that is so strange looking that the first scientists who received a description of it from Captain John Hunter in 1798 thought it was a joke. Far from being a joke, the platypus is a strong piece of evidence for the theory of evolution (not that it really needed additional ones) and, scientifically speaking, a rich source of insight into the evolution of mammals from reptile-birds (birds are considered a group of reptiles, in particular, part of the same line of…

One copy of the human genome is more than 3 billion nucleotides in length, and weighs in at about 3.5 picograms (pg, or trillionths of a gram). Only about 1.5% of this is composed of our 20,000 or so protein-coding genes, though other data suggest that at least 5% has been conserved by natural selection, suggesting that a notable portion of the non-coding majority is also functional. On the other hand, it is now apparent that much of the genome residing in our cells is made up of sequences like transposable elements -- "parasites" of the genome that can move about wwithin and be copied…

Once considered a barren plain dotted with hydrothermal vents, the seafloor's rocky regions appear to be teeming with microbial life, say scientists from the Woods Hole Oceanographic Institution (WHOI) in Woods Hole, Mass., University of Southern California (USC) in Los Angeles, and other institutions. On the deep ocean floor, microbial life is feeding on fresh volcanic rock and flourishing with greater abundance than even the most optimistic scientists thought possible. Scientists have found bacteria growing on oceanic crust in concentrations that are thousands- to ten-thousand times (three…

The description of an ancient amphibian that millions of years ago swam in quiet pools and caught mayflies on the surrounding land in Texas has set to rest one of the greatest current controversies in vertebrate evolution. The discovery was made by a research team led by scientists at the University of Calgary. The examination and detailed description of the fossil, Gerobatrachus hottoni (meaning Hotton’s elder frog), proves the previously disputed fact that some modern amphibians, frogs and salamanders evolved from one ancient amphibian group called temnospondyls. “The dispute arose because…

I’m reading a delightful history of chess, The Immortal Game, by David Shenk, and got to the chapter dealing with the dark side of chess: the fact that a small but significant number of top players throughout history have gone off the deep end -- including the famous American world champion Bobby Fisher. As is usual with correlations (playing chess => your brain goes bonk), it is not clear which way the causality goes, if at all. It could be that playing chess at the highest levels affects the mind in negative ways; it may be that abnormal minds are more likely than others to be…