Tracing Origins

Lions painting, Chauvet Cave (museum replica)

Being Human

Phylogenetic tree generated with Cytochrome Oxidase I (COI) genes.

Homo sapiens represent a branch of primates in the line of Great Apes. The family of Great Apes consists of four extant genera: Homo, Pan, Gorilla, Pongo. Karyotype analysis (Yunis et al. 1982) reveals a shared genomic structure between Great Apes. While humans have 46 chromosomes, the other Great Apes have 48. Molecular evidence at the DNA level indicates that Human Chromosome 2 is a fusion of 2 individual chromosomes. In the other Great Apes, these 2 Chromosomes are referred to as 2p and 2q to illustrate their synteny to the human counterpart.

Spread and evolution of Denisovans

In 2008, a  piece of a finger bone from a Siberian Cave was found that differed from that of modern humans. The cave, called Denisova Cave, maintains an average temperature of 0ºC year round and was suspected to contain viable soft tissue. Similar bones in this cave were discovered that had similarities to modern humans and Neandertals. An initial mitochondrial DNA analysis revealed that these beings represented a distinct line of humans that overlapped with them in time. Analysis of the full nuclear genome followed and indicated that interbreeding existed between these Denisovans, Neandertals and modern humans. Furthermore, analysis of DNA from a 400,000 year old femur in Spain revealed that these three lines diverged from the species Homo heidelbergensis and that Denisovans were closest in sequence.

Between modern humans, markers found in the mtDNA can be used to trace the migrations and origins along the maternal line. Similarly, VNTRs found on the Y chromosome have revealed migration patterns along paternal lines within men. Other markers, like the insertion points of transposable elements can be used to further describe the genetics and inheritance of modern humans while providing a snapshot into evolutionary history.

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