Vincent Sarich and Allan Wilson measured the strength of reactions between human and ape blood proteins and used this to estimate divergence times between species. Their seminal 1967 paper estimated human-ape divergence at 4-5 million years ago, contradicting the standard interpretation of 10-30 million years from fossils at the time. Subsequent discoveries like Lucy validated their younger dating estimates based on protein analysis. Later, analysis of mitochondrial and Y-chromosome DNA advanced understanding of human origins by applying the molecular clock principle to study molecular evolution. More recent research on mutation rates, chimpanzee reproduction age, and gene analysis suggests the human-chimpanzee divergence occurred between 7-13 million years ago and that early hominins like Ardip
Vincent Sarich and Allan Wilson measured the strength of reactions between human and ape blood proteins and used this to estimate divergence times between species. Their seminal 1967 paper estimated human-ape divergence at 4-5 million years ago, contradicting the standard interpretation of 10-30 million years from fossils at the time. Subsequent discoveries like Lucy validated their younger dating estimates based on protein analysis. Later, analysis of mitochondrial and Y-chromosome DNA advanced understanding of human origins by applying the molecular clock principle to study molecular evolution. More recent research on mutation rates, chimpanzee reproduction age, and gene analysis suggests the human-chimpanzee divergence occurred between 7-13 million years ago and that early hominins like Ardip
Vincent Sarich and Allan Wilson measured the strength of reactions between human and ape blood proteins and used this to estimate divergence times between species. Their seminal 1967 paper estimated human-ape divergence at 4-5 million years ago, contradicting the standard interpretation of 10-30 million years from fossils at the time. Subsequent discoveries like Lucy validated their younger dating estimates based on protein analysis. Later, analysis of mitochondrial and Y-chromosome DNA advanced understanding of human origins by applying the molecular clock principle to study molecular evolution. More recent research on mutation rates, chimpanzee reproduction age, and gene analysis suggests the human-chimpanzee divergence occurred between 7-13 million years ago and that early hominins like Ardip
Vincent Sarich and Allan Wilson measured the strength of reactions between human and ape blood proteins and used this to estimate divergence times between species. Their seminal 1967 paper estimated human-ape divergence at 4-5 million years ago, contradicting the standard interpretation of 10-30 million years from fossils at the time. Subsequent discoveries like Lucy validated their younger dating estimates based on protein analysis. Later, analysis of mitochondrial and Y-chromosome DNA advanced understanding of human origins by applying the molecular clock principle to study molecular evolution. More recent research on mutation rates, chimpanzee reproduction age, and gene analysis suggests the human-chimpanzee divergence occurred between 7-13 million years ago and that early hominins like Ardip
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The genetic revolution[edit]
The genetic revolution in studies of human evolution started when Vincent Sarich and Allan
Wilson measured the strength of immunological cross-reactions of blood serum albumin between pairs of creatures, including humans and African apes (chimpanzees and gorillas). [72] The strength of the reaction could be expressed numerically as an immunological distance, which was in turn proportional to the number of amino acid differences between homologous proteins in different species. By constructing a calibration curve of the ID of species' pairs with known divergence times in the fossil record, the data could be used as a molecular clock to estimate the times of divergence of pairs with poorer or unknown fossil records. In their seminal 1967 paper in Science, Sarich and Wilson estimated the divergence time of humans and apes as four to five million years ago, [72] at a time when standard interpretations of the fossil record gave this divergence as at least 10 to as much as 30 million years. Subsequent fossil discoveries, notably "Lucy", and reinterpretation of older fossil materials, notably Ramapithecus, showed the younger estimates to be correct and validated the albumin method. Progress in DNA sequencing, specifically mitochondrial DNA (mtDNA) and then Y-chromosome DNA (Y-DNA) advanced the understanding of human origins. [73][14][74] Application of the molecular clock principle revolutionized the study of molecular evolution. On the basis of a separation from the orangutan between 10 and 20 million years ago, earlier studies of the molecular clock suggested that there were about 76 mutations per generation that were not inherited by human children from their parents; this evidence supported the divergence time between hominins and chimpanzees noted above. However, a 2012 study in Iceland of 78 children and their parents suggests a mutation rate of only 36 mutations per generation; this datum extends the separation between humans and chimpanzees to an earlier period greater than 7 million years ago (Ma). Additional research with 226 offspring of wild chimpanzee populations in eight locations suggests that chimpanzees reproduce at age 26.5 years on average; which suggests the human divergence from chimpanzees occurred between 7 and 13 million years ago. And these data suggest that Ardipithecus (4.5 Ma), Orrorin (6 Ma) and Sahelanthropus (7 Ma) all may be on the hominid lineage, and even that the separation may have occurred outside the East African Rift region. Furthermore, analysis of the two species' genes in 2006 provides evidence that after human ancestors had started to diverge from chimpanzees, interspecies mating between "proto-human" and "proto-chimpanzees" nonetheless occurred regularly enough to change certain genes in the new gene pool: A new comparison of the human and chimpanzee genomes suggests that after the two lineages separated, they may have begun interbreeding... A principal finding is that the X chromosomes of humans and chimpanzees appear to have diverged about 1.2 million years more recently than the other chromosomes. The research suggests: There were in fact two splits between the human and chimpanzee lineages, with the first being followed by interbreeding between the two populations and then a second split. The suggestion of a hybridization has startled paleoanthropologists, who nonetheless are treating the new genetic data seriously.[75]