Recent Problems in Evolution - 2004

Table of Contents

Surprisingly rapid growth in Neanderthals

A new study compared the speed of enamel formation in teeth from over 100 Neandertal fossils compared to upper Paleolithic-Mesolithic Homo sapiens (ancient modern humans) and Homo antecessor and Homo heidelbergensis. The upper Paleolithic-Mesolithic H. sapiens exhibited identical dental development compared with modern humans. However, both Homo antecessor and Homo heidelbergensis developed much faster than modern humans while Neandertals developed even faster than their "ancestors." This study provides even more evidence that Neandertals were not ancestral to modern humans.

Ramirez, F. V., R. and J. Maria Bermudez de Castro. 2004. Surprisingly rapid growth in Neanderthals. Nature 428: 936-939 doi:10.1038/nature02428.

Identical non-coding regions in diverse vertebrate groups

Recent completion of genome sequencing for many diverse vertebrates has revealed long sequences (at least 200 bp) of non-coding DNA that are identical or nearly identical. Between humans and mice, 481 of these sequences are 100% identical. Between humans and dogs, the sequences are 99% identical. Even between humans and chickens, the sequences are 95% identical. These sequences are found on all humans chromosomes except 21 and Y. The probability is less than one chance in 1022 of finding even one such sequence in 2.9 billion bases under a simple model of neutral evolution with independent substitutions at each site. Among numerous human individuals, there is almost no sequence variation (only 6 out of over 100,000 bases). The highly unlikely existence of these identical sequences indicate that they must absolutely required for survival, since the natural mutation rate in humans would have been expected to produce at least 20 times more variation than what is observed.

Bejerano, G., M. Pheasant, I. Makunin, S. Stephen, W. J. Kent, J. S. Mattick, and D. Haussler. 2004. Ultraconserved Elements in the Human Genome. Science 10.1126/science.1098119.

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Last Modified May 11, 2004