COLOR KEY: Artificial Life; Origin of Life, Eukaryotes, Organelles;
Origin/Evolution of Prokaryotes, Viruses, Introns, etc.
Ancient Birds; Dinosaurs; Other Ancient Reptiles
Human Origins and Evolution; Domestication
Other Evolutionary Biology
Political, Religious, and Educational Issues
Jul. Our Inner Neandertal. Scientific American (July, 2010). "Genome analysis indicates Neandertals and modern humans interbred."
Jul 29. Convergent evolution of chicken Z and human X chromosomes by expansion and gene acquisitio. Nature 466:612. "Birds and mammals have distinct sex chromosomes: in birds, males are ZZ and females ZW; in mammals, males are XY and females XX. By sequencing the chicken Z chromosome and comparing it with the human X chromosome, these authors overturn the currently held view that these chromosomes have diverged little from their autosomal progenitors. The Z and X chromosomes seem to have followed convergent evolutionary trajectories, despite evolving with opposite systems of heterogamety."
Jul 15. New Oligocene primate from Saudi Arabia and the divergence of apes and Old World monkeys. Nature 466:360. "The fossil record of primates is sparse, and many gaps remain in our knowledge. One gap relates to the divergence within the catarrhines — the ancestors of hominoids (apes and humans) and Old World monkeys. The discovery of a previously unknown catarrhine in Saudi Arabia, dated to 29–28 million years ago, helps to fill in some details. This specimen shows very few catarrhine specializations, suggesting that the divergence between Old World monkeys and hominoids must have occurred after this date."
Jul 8. Dreampond revisited. Nature 466:174. "A once-threatened population of African fish is now providing a view of evolution in action. Laura Spinney asks what Lake Victoria cichlids have revealed about speciation."
Jul 1. Origins of multicellularity. Nature 466:41. "Interpreting truly ancient fossils is an especially tricky business. The conclusion that 2.1-billion-year-old structures from Gabon are the remains of large colonial organisms will get palaeobiologists talking."
Jul 1. The giant bite of a new raptorial sperm whale from the Miocene epoch of Peru. Nature 466:105. "Modern sperm whales have relatively small teeth and feed by suction, but the discovery of large teeth in the fossil record suggests that raptorial sperm whales once existed. Here the authors report the discovery of the teeth and jaws of a fossil raptorial sperm whale from the Middle Miocene of Peru, almost as large as a modern sperm whale but with a three-metre head and jaws full of teeth, some 36cm long."
Jun. Fossils Of Our Family. Scientific American (June, 2010). "A new human species is identified, but does it belong on the line leading to Homo sapiens?"
Jun. Did Neandertals Think Like Us? Scientific American (June, 2010). "João Zilhão defends his controversial view that our oft-maligned relatives shared our cognitive abilities."
Jun 25. Lucy's 'Big Brother' Reveals New Facets of Her Species. Science 328:1619. "The partial skeleton of a large male of Australopithecus afarensis, unveiled this week, is nicknamed "Big Man" because it's larger than the famous Lucy skeleton."
Jun 24. Evolutionary biology: Expanding islands of speciation. Nature 465:1019. "Speciation can occur even when the incipient species coexist and can interbreed. An extensive analysis of two fruitfly strains suggests that many genomic regions contribute to speciation in such cases."
Jun 17. Ecological interactions are evolutionarily conserved across the entire tree of life. Nature 465:918. "It is expected that closely related organisms are more likely to show similar ecological interactions than less related ones. But this has been tested only for certain types of interaction, and in a restricted set of taxa. Now interaction networks have been constructed for 116 different clades of related organisms, across the entire tree of life, and including all types of interaction. The results reveal significant conservatism across the board, including both specialist and generalist species."
Jun 17. Sequence space and the ongoing expansion of the protein universe. Nature 465:922. "The need to maintain the structural and functional integrity of an evolving protein limits the range of acceptable amino-acid substitutions — but to what extent does this constrain how far homologous protein sequences can diverge? Here, sequence divergence data are used to explore the limits of protein evolution, and to conclude that ancient proteins are continuing to diverge from one another, indicating that the protein sequence universe is slowly expanding."
Jun 3. The Ectocarpus genome and the independent evolution of multicellularity in brown algae. Nature 465:617. "The genome of Ectocarpus siliculosis, a model for the study of brown algae, has been sequenced. These seaweeds are complex photosynthetic organisms that have adapted to rocky coastal environments. Genome analysis sheds light on this adaptation, revealing an extended set of light-harvesting and pigment biosynthesis genes, and new metabolic processes such as halide metabolism. Comparative analyses are also significant with respect to the evolution of multicellularity in plants, animals and brown algae."
Jun 3. Natural allelic variation underlying a major fitness trade-off in Arabidopsis thaliana. Nature 465:632. "Here, a combination of forward genetics and genome-wide association analyses has been used to show that variation at a single genetic locus in Arabidopsis thaliana underlies phenotypic variation in vegetative growth as well as resistance to infection. The strong enhancement of resistance mediated by one of the alleles at this locus explains the allele's persistence in natural populations throughout the world, even though it drastically reduces the production of new leaves."
May-June. Development Influences Evolution. American Scientist (May-June, 2010). "A range of factors—including genetics and physics, location and timing— can either constrain an animal’s features or amplify changes."
May 28. Prion Strain Mutation and Selection. Science 328:1111-1112. "Structural compatibility of infecting prion proteins with those of a new host determine whether they will be successfully transmitted."
May 27. Palaeontology: A little Kraken wakes. Nature 465:427. "Fossils from the famed Burgess Shale continue to deliver fresh perspectives on a dramatic episode in evolutionary time. The latest revelations bear on the early history of cephalopod molluscs."
May 27. Primitive soft-bodied cephalopods from the Cambrian. Nature 465:469. "The 505-million-year-old Burgess Shales of British Columbia are justifiably famous for the exquisite preservation of their fossils, and for the extreme oddity of many of them. One such is Nectocaris pteryx, which, from the few fossils available for study, looked like a chordate fused with an arthropod. However, the collection and examination of more fossils of Nectocaris suggests that it in fact represents an early offshoot of cephalopod molluscs — a kind of squid, though with two rather than eight or ten tentacles."
May 13. A formal test of the theory of universal common ancestry. Nature 465:219. "It is generally assumed that life had a single origin — or, at least, that all extant life descended from a 'universal common ancestor' (UCA) — although this view has been called into question by evidence for extensive horizontal gene transfer. Here, the UCA view is framed as a formal hypothesis and tested (crucially, without assuming that genetic similarity reflects genetic kinship). The UCA view triumphs: a single origin of life is overwhelmingly more likely than any competing hypothesis."
Apr 29. Exceptional dinosaur fossils show ontogenetic development of early feathers. Nature 464:1338. "Study of two specimens of the feathered dinosaur Similicaudipteryx shows that the morphology of dinosaur feathers changed dramatically as the animals matured. Moreover, the morphology of feathers in dinosaurs was much more varied than one would expect from looking at feathers in modern birds."
Apr 29. Evolution of self-compatibility in Arabidopsis by a mutation in the male specificity gene. Nature 464:1342. "Self-fertilisation (selfing) in plants is prevented mainly by the self-incompatibility recognition system, which consists of male and female specificity genes and modifier genes. Selfing does occur in Arabidopsis plants, but it is not known how it arose. Here it is reported that selfing in Arabidopsis results from a geographically widespread, 213-base-pair inversion within the male specificity gene. When this inversion is returned to its original orientation, selfing is prevented once more."
Apr 29. A role for host–parasite interactions in the horizontal transfer of transposons across phyla. Nature 464:1347. "'Horizontal gene transfer' refers to the passage of genetic material between non-mating species. Transposable elements (transposons) may be especially prone to horizontal gene transfer, but the mechanisms by which they can spread across diverged species have been elusive. Here it is shown that transposons can spread by hitchhiking in the genomes of parasites. The amount of DNA that can be transferred in this way underscores the impact of horizontal gene transfer on genome evolution."
Apr 23. Complexity and Diversity. Science 328:494-497. "Eco-evolutionary models of selection acting on multiple traits show how rare alleles can establish and drive speciation."
Apr 22. Generation of a novel wing colour pattern by the Wingless morphogen. Nature 464:1143. "Here, the generation and evolution of the complex spotted wing pattern of Drosophila guttifera are investigated. The findings show that wing spots are induced by the Wingless morphogen, and that the elaborate spot pattern evolved from simpler schemes by co-option of Wingless expression at new sites. This type of process is likely to occur in other animals, too."
Apr 15. Périgord black truffle genome uncovers evolutionary origins and mechanisms of symbiosis. Nature 464:1033. "The genome of the black truffle - one of the most popular truffles on the market - has been sequenced. This is the first genome of a symbiotic ascomycete to be analysed. Comparison with the genome of another ectomycorrhizal symbiotic fungus indicates that a genetic predisposition to symbiosis evolved differently in ascomycetes and basidiomycetes. The study also offers insight into fungal sex and fruiting."
Apr 8. Evolutionary biology: A flourishing of fish forms. Nature 464:840. "According to an innovative exercise in 'morphospace analysis', modern fish owe their stunning diversity in part to an ecological cleaning of the slate by the mass extinction at the end of the Cretaceous."
Apr 8. The complete mitochondrial DNA genome of an unknown hominin from southern Siberia. Nature 464:894. "Ancient mitochondrial DNA from a hominin individual who lived in the mountains of Central Asia between 48,000–30,000 years ago has been sequenced. Comparative genomics suggest that this mitochondrial DNA derives from an out-of-Africa migration distinct from the ones that gave rise to Neanderthals and modern humans. It also seems that this hominin lived in close spatio-temporal proximity to Neanderthals and modern humans."
Apr 8. Genome-wide SNP and haplotype analyses reveal a rich history underlying dog domestication. Nature 464:898. "An extensive genome-wide survey of over 48,000 single nucleotide polymorphisms in dogs and their wild progenitor, the grey wolf, was conducted to shed light on the process of dog diversification. The results reveal that much of genome diversity came from Middle Eastern progenitors, combined with interbreeding with local wolf populations, and that recent evolution involved limited genetic variation to create the phenotypic diversity of modern dogs."
Mar 25. Whole-genome resequencing reveals loci under selection during chicken domestication. Nature 464:587. "Here, the genomes of birds representing eight populations of domestic chickens are compared with the genome of their wild ancestor, the red jungle fowl. The results reveal selective sweeps of favourable alleles and mutations that may have contributed to domestication. One selective sweep, for instance, occurred at the locus encoding the thyroid stimulating hormone receptor, which is important in metabolism and in the timing of vertebrate reproduction."
Mar 19. Male Rivalry Extends to Sperm in Female Reproductive Tract. Science 327:1443. "Two papers published by Science this week, one on work in ants and bees and the other on work in fruit flies, demonstrate that sperm competition between males continues even after the sperm enters the female."
Mar 18. Post-copulatory sexual selection and sexual conflict in the evolution of male pregnancy. Nature 464:401. "Male pregnancy is restricted to seahorses, pipefishes and their relatives, in which young are nurtured in the male's brood pouch. It is now clear that the brood pouch has a further function. Studies of Gulf pipefish show that males can selectively abort embryos from females perceived as less attractive, saving resources for more hopeful prospects later. This is the only known example of post-copulatory sexual conflict in a sex-reversed species."
Mar 11. Compensatory evolution in mitochondrial tRNAs navigates valleys of low fitness. Nature 464:279. "Evolution from one fitness peak to another must involve either transitions through intermediates of low fitness or skirting round the fitness valley through compensatory mutations elsewhere. Here, the base pairs in mitochondrial tRNA stems is used as a model to show that deep fitness valleys can be traversed. Transitions between AU and GC pairs have occurred during mammalian evolution without help from genetic drift or mutations elsewhere."
February. The Naked Truth: Why Humans Have No Fur. Scientific American. "Recent findings lay bare the origins of human hairlessness—and hint that naked skin was a key factor in the emergence of other human traits."
Nature
Feb 11. Evolutionary biology: Face of the past reconstructed. Nature 463:739. "DNA is particularly well preserved in hair — enabling the genome of a human to be sequenced, and his ancestry and appearance to be determined, from 4,000-year-old remains."
Feb 11. Palaeontology: Decay distorts ancestry. Nature 463:741. "Experiments with simple chordate animals show how decay may make the resulting fossils seem less evolved. The consequence is to distort evidence of the evolution of the earliest vertebrates and their precursors."
Jan 29. Bird-Dinosaur Link Firmed Up, And in Brilliant Technicolor. Science 327:508. "Paleontologists unveil Haplocheirus sollers, a new genus of alvarezsauroid—a group of dinosaurs once thought to be flightless birds. The nearly complete skeleton is about 15 million years older than the earliest known bird, Archaeopteryx."
Jan 29. Apes Among the Tangled Branches of Human Origins. Science 327:532-534. "The evolution of apes between 23 and 5 million years ago set the scene for the emergence of the first hominins in Africa."
Jan 28. Chimpanzee and human Y chromosomes are remarkably divergent in structure and gene content. Nature 463:536. "Little is known about the recent evolution of the Y chromosome because only the human Y chromosome has been fully sequenced. The sequencing of the male-specific region of the Y chromosome (MSY) in the chimpanzee and comparison between the MSYs of the two species now reveals that they differ radically in sequence structure and gene content, indicating rapid evolution over the past 6 million years."
Jan 21. New take on the Red Queen. Nature 463:306. "Biologists have assumed that natural selection shapes larger patterns of evolution through interactions such as competition and predation. These patterns may instead be determined by rare, stochastic speciation."
Jan 21. Phylogenies reveal new interpretation of speciation and the Red Queen. Nature 463:349. "The Red Queen metaphor has species accumulating small changes to keep up with a continually changing environment, with speciation occurring at a constant rate. This constant-rate claim is now tested against four competing models, using 101 phylogenies of animal, plant and fungal taxa. The results provide a new interpretation of the Red Queen; a view linking speciation to rare stochastic events that cause reproductive isolation."
Jan 21. Mutational robustness can facilitate adaptation. Nature 463:353. "If robustness is the opposite of evolvability, we might expect that a robust population would have difficulty adapting to environmental change; however, some studies have suggested that genetic robustness facilitates adaptation. Here, using a general population genetics model, mutational robustness is found to either impede or facilitate adaptation depending on the population size, the mutation rate and the structure of the fitness landscape."
Jan 7. Bornavirus enters the genome. Nature 463:39. "A survey of mammalian genomes has unexpectedly unearthed DNA derived from bornaviruses, leading to speculation about the role of these viruses in causing mutations with evolutionary and medical consequences."
Jan 7. Muddy tetrapod origins. Nature 463:40. "The tracks left by organisms are among the most difficult of fossils to interpret. But just such evidence puts debate about the origins of four-limbed vertebrates (which include ourselves) on a changed footing."
Jan 7. Tetrapod trackways from the early Middle Devonian period of Poland. Nature 463:43. "The earliest body fossils of tetrapods (vertebrates with limbs rather than paired fins) date to the Late Devonian period. There have been claims of tetrapod trackways predating these body fossils but the age and identity of the track makers have remained controversial. The discovery of well-preserved and securely dated tetrapod tracks from Polish marine tidal flat sediments of early Middle Devonian age, around 18 million years older than the earliest tetrapod body fossils, is now presented."
