East African Australopithecines: More than One Species?

The fact that two species of Australopithecus coexisted, more or less, in South Africa has been known for years. One of the more interesting South African specimens (Stw 573) is dated to somewhere between 3.5 and 3 million years. It has a divergent big toe. As does a new partial foot found in East Africa. The foot is somewhere around 3.46 MYA. Only a partial foot was found so the specimen has not been attributed to a species. The find is reported in Nature. I don’t have access to Nature, and would be grateful if someone could send me a copy of the article. I have the paper now, thanks!

Gorilla Genome Sequenced!

The gorilla genome has been sequenced and yields some interesting insights on human evolution. The research is reported in Nature. The article is open access. Here is the abstract:

Gorillas are humans’ closest living relatives after chimpanzees, and are of comparable importance for the study of human origins and evolution. Here we present the assembly and analysis of a genome sequence for the western lowland gorilla, and compare the whole genomes of all extant great ape genera. We propose a synthesis of genetic and fossil evidence consistent with placing the human–chimpanzee and human–chimpanzee–gorilla speciation events at approximately 6 and 10 million years ago. In30%of the genome, gorilla is closer tohuman or chimpanzee than the latter are to each other; this is rarer around coding genes, indicating pervasive selection throughout great ape evolution, and has functional consequences in gene expression. A comparison of protein coding genes reveals approximately 500 genes showing accelerated evolution on each of the gorilla, human and chimpanzee lineages, and evidence for parallel acceleration, particularly of genes involved in hearing.Wealso compare the western and eastern gorilla species, estimating an average
sequence divergence time 1.75 million years ago, but with evidence for more recent genetic exchange and a population bottleneck in the eastern species. The use of the genome sequence in these and future analyses will promote a deeper understanding of great ape biology and evolution.

Impact Theory: The Theory That Would Not Die

The impact theory rears its head again! From Science Dailey:

Conducting a wide range of exhaustive tests, the researchers conclusively identified a family of nanodiamonds, including the impact form of nanodiamonds called lonsdaleite, which is unique to cosmic impact. The researchers also found spherules that had collided at high velocities with other spherules during the chaos of impact. Such features, Kennett noted, could not have formed through anthropogenic, volcanic, or other natural terrestrial processes. “These materials form only through cosmic impact,” he said.

Kennett is refering to material found in a 13,000 year old layer of sediment on the floor of Lake Cuitzeo. The research is reported in PNAS and is open access.