Generation and annotation of the DNA sequences of human chromosomes 2 and 4
LaDeana W. Hillier, et al. 2005. Nature 434: 724-731

Abstract:
Human chromosome 2 is unique to the human lineage in being the product of a head-to-head fusion of two intermediate-sized ancestral chromosomes. Chromosome 4 has received attention primarily related to the search for the Huntington’s disease gene, but also for genes associated with Wolf-Hirschhorn syndrome, polycystic kidney disease and a form of muscular dystrophy. Here we present approximately 237 million base pairs of sequence for chromosome 2, and 186 million base pairs for chromosome 4, representing more than 99.6% of their euchromatic sequences. Our initial analyses have identified 1,346 protein-coding genes and 1,239 pseudogenes on chromosome 2, and 796 protein-coding genes and 778 pseudogenes on chromosome 4. Extensive analyses confirm the underlying construction of the sequence, and expand our understanding of the structure and evolution of mammalian chromosomes, including gene deserts, segmental duplications and highly variant regions.


Early Homo at Swartkrans, South Africa: a review of the evidence and an evaluation of recently proposed morphs
Grine, F. E. Jan/Feb 2005. South African Journal of Science 101 (1/2): 43-52

Abstract:
The site of Swartkrans provided the first evidence for the contemporaneity of two early hominin genera, Paranthropus and Homo. In large measure, the fossils that are attributable to Homo consist of incomplete fragments and isolated teeth, which has led to an understandable degree of controversy regarding their taxonomic affinities. While all authorities seem to be in agreement that the Swartkrans australopith fossils constitute a single species, P. robustus, the number, identity and affinities of the species of Homo represented in these deposits remain unresolved issues. It has been proposed most recently that several distinct 'morphs' of this genus are represented at this site. However, a number of the specimens comprising these proposed morphological groups have been misidentified either taxonomically or anatomically. As such, the validity of these proposed associations and the morphological distinctions that might have characterized them are compromised. The proposition that more than one 'morph', or species, of Homo is represented at Swartkrans is neither novel nor unreasonable, but the evidence that has been cited most recently does not lend support to such a conclusion.


First occurrence of early Homo in the Nachukui Formation (West Turkana, Kenya) at 2.3-2.4 Myr
Sandrine Prat, et al. 2005. Journal of Human Evolution 49(2): 230-240

Abstract:
Cognitive abilities and techno-economic behaviours of hominids in the time period between 2.6-2.3 Myr have become increasingly well- documented. This time period corresponds to the oldest evidence for stone tools at Gona (Kada Gona, West Gona, EG 10-12, OGS 6-7), Hadar (AL 666), lower Omo valley (Ftji1, 2 & 5, Omo 57, Omo 123) in Ethiopia, and West Turkana (Lokalalei sites -LA1 & LA2C-) in Kenya. In 2002 a new palaeoanthropological site (LA1¦Á), 100 meters south of the LA1 archaeological site, produced a first right lower molar of a juvenile hominid (KNM-WT 42718). The relative small size of the crown, its marked MD elongation and BL reduction, the relative position of the cusps, the lack of a C6 and the mild expression of a protostylid, reinforced by metrical analyses, demonstrate the distinctiveness of this tooth compared with Australopithecus afarensis, A. anamensis, A. africanus and Paranthropus boisei, and its similarity to early Homo. The LA1¦Á site lies 2.2 m above the Ekalalei Tuff which is slightly younger than Tuff F dated to 2.34 ¡À 0.04 Myr. This juvenile specimen represents the oldest occurrence of the genus Homo in West Turkana.


Genomic evolution of MHC class I region in primates
Kaoru Fukami-Kobayashi, et al. 2005. PNAS, 20 June published online

Abstract:
To elucidate the origins of the MHC-B-MHC-C pair and the MHC class I chain-related molecule (MIC)A-MICB pair, we sequenced an MHC class I genomic region of humans, chimpanzees, and rhesus monkeys and analyzed the regions from an evolutionary standpoint, focusing first on LINE sequences that are paralogous within each of the first two species and orthologous between them. Because all the long interspersed nuclear element (LINE) sequences were fragmented and nonfunctional, they were suitable for conducting phylogenetic study and, in particular, for estimating evolutionary time. Our study has revealed that MHC-B and MHC-C duplicated 22.3 million years (Myr) ago, and the ape MICA and MICB duplicated 14.1 Myr ago. We then estimated the divergence time of the rhesus monkey by using other orthologous LINE sequences in the class I regions of the three primate species. The result indicates that rhesus monkeys, and possibly the Old World monkeys in general, diverged from humans 27-30 Myr ago. Interestingly, rhesus monkeys were found to have not the pair of MHC-B and MHC-C but many repeated genes similar to MHC-B. These results support our inference that MHC-B and MHC-C duplicated after the divergence between apes and Old World monkeys.


Anatomical descriptions, comparative studies and evolutionary significance of the hominin skulls from Dmanisi, Republic of Georgia
G. Philip Rightmire, David Lordkipanidze and Abesalom Vekua. Journal of Human Evolution, Available online 4 November 2005

Abstract:
Evidence for ancient hominin occupation in Eurasia comes from Dmanisi in the Georgian Caucasus. Stratigraphic and sedimentological arguments, geochemical observations, paleomagnetic sampling and radiometric dates all point to the conclusion that bones and artifacts were deposited at this site during a brief interval following the close of the Olduvai Subchron (1.77 million years ago). In this report we present further descriptive and comparative studies of the D2280 braincase, the D2282 partial cranium, now linked with the D211 mandible, and the skull D2700/D2735. The crania have capacities ranging from 600 cm3 to 775 cm3. Supraorbital tori and other vault superstructures are only moderately developed. The braincase is expanded laterally in the mastoid region, but the occiput is rounded. The pattern of sagittal keeling is distinctive. D2700 displays a prominent midfacial profile and has a very short nasoalveolar clivus. Also, the M3 crowns are reduced in size. Although there is variation probably related to growth status and sex dimorphism, it is appropriate to group the Dmanisi hominins together. With the possible exception of the large D2600 mandible, the individuals are sampled from one paleodeme. This population resembles Homo habilis in brain volume and some aspects of craniofacial morphology, but many of these features can be interpreted as symplesiomorphies. Other discrete characters and measurements suggest that the Dmanisi skulls are best placed with H. erectus. There are numerous similarities to individuals from the Turkana Basin in Kenya, but a few features link Dmanisi to Sangiran in Java. Some traits expressed in the Dmanisi assemblage appear to be unique. Reconstructing the evolutionary relationships of these ancient populations of Africa and Eurasia is difficult, as the record is quite patchy, and determination of character polarities is not straightforward. Nevertheless, the evidence from anatomical analysis and measurements supports the hypothesis that Dmanisi is close to the stem from which H. erectus evolved.


Generation and annotation of the DNA sequences of human chromosomes 2 and 4
LaDeana W. Hillier, et al. Nature 434, 724-731 (7 April 2005)

Abstract:
Human chromosome 2 is unique to the human lineage in being the product of a head-to-head fusion of two intermediate-sized ancestral chromosomes. Chromosome 4 has received attention primarily related to the search for the Huntington's disease gene, but also for genes associated with Wolf-Hirschhorn syndrome, polycystic kidney disease and a form of muscular dystrophy. Here we present approximately 237 million base pairs of sequence for chromosome 2, and 186 million base pairs for chromosome 4, representing more than 99.6% of their euchromatic sequences. Our initial analyses have identified 1,346 protein-coding genes and 1,239 pseudogenes on chromosome 2, and 796 protein-coding genes and 778 pseudogenes on chromosome 4. Extensive analyses confirm the underlying construction of the sequence, and expand our understanding of the structure and evolution of mammalian chromosomes, including gene deserts, segmental duplications and highly variant regions.

The press release for the above article is at http://news-info.wustl.edu/news/page/normal/5045.html?emailID=4976.

Additional relevant information can be found at:
http://www.evolutionpages.com/chromosome_2.htm,
http://www.evolutionpages.com/homo_pan_divergence.htm
http://en.wikipedia.org/wiki/Chimpanzee_Genome_Project
http://www.youtube.com/watch?v=Gs1zeWWIm5M


Human and NonHuman Primate Brains: Are They Allometrically Scaled Versions of the Same Design ?
James K. Rilling. Evolutionary Anthropology 15(2): 65-77, March/April 2006

Abstract:
Allometric analyses of brain structure sizes across the primate order demonstrate that human, ape, and other anthropoid brains are not simply allometrically scaled versions of the same generalized design. Both human and ape brains exhibit specializations with respect to other anthropoid brains. Ape specializations include elaboration of the cerebellum (all apes) and frontal lobes (great apes only), and probably connectivity between them. Human brain specializations include an overall larger proportion of neocortex, with disproportionate enlargement of prefrontal and temporal association cortices; an apparent increase in cerebellar connections with cerebral cortical association areas involved in cognition; and a probable augmentation of intracortical connectivity in prefrontal cortex.


A new radiocarbon revolution and the dispersal of modern humans in Eurasia
Paul Mellars. Nature 439(23): 931-935, February 2006

Abstract:
Radiocarbon dating has been fundamental to the study of human cultural and biological development over the past 50,000 yr. Two recent developments in the methodology of radiocarbon dating show that the speed of colonization of Europe by modern human populations was more rapid than previously believed, and that their period of coexistence with the preceding Neanderthal was shorter.

With a critique by Professor John Hawks at http://johnhawks.net/weblog/reviews/archaeology/upper/radiocarbon_calibration_mellars_2006.html.


A juvenile early hominin skeleton from Dikika, Ethiopia
Zeresenay Alemseged, et al. Nature 443(21): 296-301 September 2006

Abstract
Understanding changes in ontogenetic development is central to the study of human evolution. With the exception of Neanderthals, the growth patterns of fossil hominins have not been studied comprehensively because the fossil record currently lacks specimens that document both cranial and postcranial development at young ontogenetic stages. Here we describe a well-preserved 3.3-million-year-old juvenile partial skeleton of Australopithecus afarensis discovered in the Dikika research area of Ethiopia. The skull of the approximately three-year-old presumed female shows that most features diagnostic of the species are evident even at this early stage of development. The find includes many previously unknown skeletal elements from the Pliocene hominin record, including a hyoid bone that has a typical African ape morphology. The foot and other evidence from the lower limb provide clear evidence for bipedal locomotion, but the gorilla-like scapula and long and curved manual phalanges raise new questions about the importance of arboreal behaviour in the A. afarensis locomotor repertoire.

Additional relevant information can be found at:
Kate Wong. Special Report: Lucy's Baby
Kate Wong. Expert Commentary on Lucy's Baby: C. Owen Lovejoy


Patterns of size sexual dimorphism in Australopithecus afarensis: Another look
S.-H. Lee. Homo - Journal of Comparative Human Biology 56(3): 219-232, 8 December 2005

Abstract:
Size sexual dimorphism is one of the major components of morphological variation and has been associated with socioecology and behavioral variables such as mating patterns. Although several studies have addressed the magnitude and pattern of sexual dimorphism in Australopithecus afarensis, one of the earliest hominids, consensus has yet to be reached. This paper uses assigned resampling method, a data resampling method to estimate the magnitude of sexual dimorphism without relying on individual sex assessments, to examine the fossil hominid sample from Hadar. Two questions are asked: first, whether sexual dimorphism in a selected sample of skeletal elements of A. afarensis is the same as that in living humans, chimpanzees, or gorillas; and second, whether different skeletal elements reflect variation in sexual dimorphism in the same way. All possible metric variables were used as data in applying the method, including seven variables from three elements (mandibular canine, humerus, femur). Analyses show that A. afarensis is similar in size sexual dimorphism to gorillas in femoral variables, to humans in humeral variables, and to chimpanzees in canine variables. The results of this study are compatible with the hypothesis that the pattern of sexual dimorphism in A. afarensis is different from any that are observed in living humans or apes.