Continuous vegetation record of the Greater Cape Floristic Region (South Africa) covering the past 300 000 years (IODP U1479)

The Greater Cape Floristic Region (GCFR) of South Africa is a biodiversity hotspot of global significance, and its archeological record has substantially contributed to the understanding of modern human origins. For both reasons, the climate and vegetation history of southwestern South Africa is of interest to numerous fields. Currently known paleoenvironmental records cover the Holocene, the last glacial–interglacial transition and parts of the last glaciation but do not encompass a full glacial–interglacial cycle. To obtain a continuous vegetation record of the last Pleistocene glacial–interglacial cycles, we studied pollen, spores and micro-charcoal of deep-sea sediments from IODP Site U1479 retrieved from SW of Cape Town. We compare our palynological results of the Pleistocene with previously published results of Pliocene material from the same site. We find that the vegetation of the GCFR, in particular fynbos and afrotemperate forest, responds to precessional forcing of climate. The micro-charcoal record confirms the importance of fires in the fynbos vegetation. Ericaceae-rich and Asteraceae-rich types of fynbos could extend on the western part of the Paleo-Agulhas Plain (PAP), which emerged during periods of low sea level of the Pleistocene.

Ancient uniparental DNAs in distinguishing the competing theories of molecular evolution and modern human origins

Analyses of extant people have resulted in two models for the uniparental DNA phylogenetic trees of modern humans rooted in either Africa or East Asia. The Africa model is based on the neutral theory. The Asia model is reached from the maximum genetic diversity (MGD) theory. To test the two competing theories, we examined published data of ancient uniparental DNAs. Many ancient samples belonging to a terminal haplogroup were found to have mutated only in some, but not all, of the sites that define a more basal haplogroup. This pattern was found for the non-controversial haplogroups shared by the two competing models, and also for the haplogroups specific to the Asia model. Furthermore, many ancient samples that do not belong to some of the haplogroups of the Africa model nonetheless had mutations in them, which makes it impossible to unambiguously assign them to a haplogroup within the Africa model. Finally, uniparental DNAs of archaic humans were found to carry some modern alleles present in the first uniparental DNAs in the Asia model, indicating convergent evolution. Therefore, the data from ancient DNAs have verified the MGD theory and the actual existence of the haplogroups specific to the Asia model.

Continuous vegetation record of the Greater Cape Floristic Region (South Africa) covering the past 300 thousand years (IODP U1479)

The flora of the Greater Cape Floristic Region (GCFR) of South Africa is a biodiversity hotspot of global significance, and its archaeological record has contributed substantially to the understanding of modern human origins. For both reasons, the climate and vegetation history of south-western South Africa is of interest to numerous fields. Currently known paleo-environmental records cover the Holocene, the last glacial-interglacial transition and parts of the last glaciation but do not encompass a full glacial-interglacial cycle. To obtain a continuous vegetation record of the last Pleistocene glacial-interglacial cycles, we studied pollen, spores and micro-charcoal of deep-sea sediments from IODP Site U1479 retrieved from SW of Cape Town. We compare our palynological results of the Pleistocene with previously published results of Pliocene material from the same site. We find that the vegetation of the GCFR, in particular Fynbos and Afrotemperate forest, respond to precessional forcing of climate. The micro-charcoal record confirms the importance of fires in the Fynbos vegetation. Ericaceae-rich and Asteraceae-rich types of Fynbos could extend on the western part of the Palaeo-Agulhas Plain (PAP), which emerged during periods of low sea-level of the Pleistocene.

Pleistocene large reptile tracks and probable swim traces on South Africa’s Cape south coast

The Cape south coast of South Africa contains a wealth of Pleistocene vertebrate trace fossil sites in aeolianites and cemented foreshore deposits. Published studies have described mammal and avian tracksites identified along this coastline. We report here on a number of Pleistocene palaeosurfaces within the Garden Route National Park that exhibit tracks of large reptiles, including probable swim traces. The tracks were probably made by more than one species, and may include a crocodylian. There are no extant reptiles in this coastal region capable of making such tracks and traces, which probably represent an indication of a previously more extensive range for the Nile crocodile and a monitor lizard. These findings demonstrate the potential for ichnology to complement the traditional body fossil record. Two Middle Stone Age stone artifacts were found embedded in one palaeosurface containing multiple reptile trackways. These discoveries have implications for the understanding of Pleistocene palaeoenvironment and palaeoclimate – in an area which is important in the study of modern human origins.

The Out of East Asia model versus the African Eve model of modern human origins in light of ancient mtDNA findings

The first molecular model of modern human origins published in 1983 had the mtDNA phylogenetic tree rooted in Asia. This model was subsequently overlooked and superseded by the African Eve model in 1987 that was premised on the unrealistic infinite site assumption and the now failed molecular clock hypothesis. We have recently developed a new framework of molecular evolution, the maximum genetic diversity (MGD) hypothesis, which has in turn led us to discover a new model of modern human origins with the roots of uniparental DNAs placed in East Asia. While the African mtDNA Eve model has haplotype N as ancestral to R, our Asia model places R as the ancestor of all. We here examined ancient mtDNAs from the literature focusing on the relationship between N and R. The data showed that all three oldest mtDNAs were R with the 45000 year old Ust-Ishim a basal type and the two ~40000 year old samples sub-branch of R. Among the numerous mtDNAs of 39500-30000 year old, most were R subtype U and only two were N samples, the 39500 year old Oase1 and the 34425 year old Salkhit. These N types are basal and hence likely close to the root of N. These ancient DNA findings suggest that basal R is ~5000 years older than basal N, thereby confirming the East Asia model and invalidating the African Eve model.