View Full Version : Getting our wires uncrossed on human evolution

Jean M
11-28-2013, 03:06 PM
Carles Lalueza-Fox, Agreements and Misunderstandings among Three Scientific Fields: Paleogenomics, Archaeology, and Human Paleontology, Current Anthropology, online 8 November 2013 ahead of print.

The emergence of paleogenomics (the study and analysis of ancient genomes) has provided a new, powerful source of information that can be used to test previous hypotheses regarding human evolution. However, various misunderstandings concerning the interpretation of genetic data in an archaeological and paleontological context and the existence of different scientific goals tend to hinder the fluent and fruitful collaboration between these fields. Here we explore some of the subjects creating confusion, such as the problems associated with molecular clocks, the difference between sequence divergence and species divergence, and the limitations of the uniparental markers. Limited understanding of how the expression of a genome shapes the phenotype (including morphology and cognition) is the main obstacle to linking the genetic and the morphological evidence available. In the case of Neanderthals (and probably Denisovans, too), it is obvious that the conspicuous morphological differences cannot be explained by differences in a list of about 100 genes alone, thus suggesting that regulatory genomic elements must have been involved. A functional analysis of the genes involved as well as a study of the genomic architecture—a complexity level above the simple DNA message—could help us fill this gap. It is hoped that this future work will lead to the emergence of an interrelated and multidisciplinary view of the study of the past based on real collaborative efforts among disciplines.

The interaction between archaeologists, paleontologists, and researchers from the emerging field of paleogenomics has traditionally been plagued by misunderstandings and a lack of collaborative efforts. Over the last three decades, molecular biologists working on population analysis of human samples have usually tried to fit their results to hypotheses proposed previously on the basis of morphological or archaeological studies. These hypotheses were often chosen at random from the available literature by the authors of these population genetics studies, who were clearly unfamiliar with the current state of the art in these other fields. Furthermore, the genetic results themselves—especially with data, such as mitochondrial DNA sequences, with limited phylogenetic resolving power—frequently did not allow the favoring of one hypothesis over another.... In the future, we can expect that an interrelated and multidisciplinary view of our study of the past will be possible, and this can only be achieved with direct and real collaboration.

He covers

Molecular Clocks, Sequence Divergence, and Species Divergence
Mitochondrial DNA: Limitations of Uniparental Markers
Gene Flow from Archaic Hominins
Limitations of the First Neanderthal Genome Draft
Beyond the Genome
An Example of a Regulatory Element: microRNA
Convergent Evolution
Future Directions

S9 H9
12-01-2013, 04:01 PM
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