Recent Problems in Evolution - 2000

Table of Contents

Discrepancy of genetic and fossil appearance dates of vertebrates

Paleontologists believe that vertebrates diverged from a lancelet-like relative sometime in the Cambrian period, which began 545 million years ago. However, molecular studies of gene similarities between lancelets and today's vertebrates suggest that the vertebrate lineage diverged 750 million years ago. Recent fossil finds do not resolve this discrepancy. Haikouella, sliver-shaped lancelet-like organisms that have eyes and probably have a primitive brain, have been dated to 530 million years ago. Recently discovered conodonts, previously classified into a number of different phyla, seem to be full-fledged vertebrates, even more similar to living jawed fish than to lampreys or hagfish. However, these fossils date to 510 million years ago at the earliest.

Zimmer, C. 2000. In Search of Vertebrate Origins: Beyond Brain and Bone. Science 287: 1576-1579.

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Neanderthal baby attacks evolutionary dogma

Stepping out 29,000 years from the past, a Neanderthal baby has taught evolutionists a thing or two about human origins, and strengthened the case for special creation. In a just published study, scientists extracted mt Deoxyribonucleic acid: the chemical inside the nucleus of a cell that carries the genetic instructions for making living organisms.DNA from a Neanderthal infant skeleton found in the northern Caucasus near the Black Sea and laid to rest any question of whether Neanderthals could have been our ancestors. A previous study had examined a 397 Two nucleotides on opposite complementary DNA or RNA strands that are connected via hydrogen bonds.base pair Neanderthal Genetic material found in mitochondria, the organelles that generate energy for the cell.mtDNA fragment and compared it with a Genetic material found in mitochondria, the organelles that generate energy for the cell.mtDNA The order of nucleotides in a DNA or RNA molecule, or the order of amino acids in a protein molecule.sequenceof 986 One of the structural components, or building blocks, of DNA and RNA. A nucleotide consists of a base plus a molecule of sugar and one of phosphate.nucleotide pairs from living humans of diverse ethnic backgrounds. The results showed an enormous 26 One of the structural components, or building blocks, of DNA and RNA. A nucleotide consists of a base plus a molecule of sugar and one of phosphate.nucleotide Two nucleotides on opposite complementary DNA or RNA strands that are connected via hydrogen bonds.base pair difference between the Neanderthal and Human Genetic material found in mitochondria, the organelles that generate energy for the cell.mtDNA (a 6.5% difference, which is almost as much as the average difference between human Genetic material found in mitochondria, the organelles that generate energy for the cell.mtDNA and chimpanzee Genetic material found in mitochondria, the organelles that generate energy for the cell.mtDNA, which is 8.9%). In this region of the Genetic material found in mitochondria, the organelles that generate energy for the cell.mtDNA, modern humans differ from one another in an average of eight Two nucleotides on opposite complementary DNA or RNA strands that are connected via hydrogen bonds.base pairs, and those differences were completely independent of the 26 observed for the Neanderthal fossil. In the current study, a 357 Two nucleotides on opposite complementary DNA or RNA strands that are connected via hydrogen bonds.base pair The order of nucleotides in a DNA or RNA molecule, or the order of amino acids in a protein molecule.sequence of Genetic material found in mitochondria, the organelles that generate energy for the cell.mtDNA was examined and found to vary from modern human The order of nucleotides in a DNA or RNA molecule, or the order of amino acids in a protein molecule.sequences at 23 bases (6.4%), nineteen of which were identical to those of the first Neanderthal. A summary of the findings of the two studies can be found in the table below:

Sequence Differences Between Modern Humans and Neanderthals
Genetic material found in mitochondria, the organelles that generate energy for the cell.mtDNA
Sample

Sequence Number (Read Down)
11111111111111111111111111111111111111
66666666666666666666666666666666666666
00001111111111111122222222222222333333
37890011123455688802334455566679124669
78637812899846923993043408612389104253

Modern
Human
AATTCCCCGGACTGCAATTCACTGCCACC-CATCCTCC
Neanderthal1 GG.CTTTT.ATTC.T.CCCTGT.A.GA.TATGCT.C..
Neanderthal2  .C......ATT.ATCCCCTGT.A.A..TATGCTTC..

The analysis of the infant's Deoxyribonucleic acid: the chemical inside the nucleus of a cell that carries the genetic instructions for making living organisms.DNA was extremely important, since it was dated at 29,000 years ago - only 1000 years before the last Neanderthal disappeared. If Neanderthals and humans had interbred, one should have expected to see this in the last remnants of the Neanderthals. In addition, since the two Neanderthal fossils were separated geographically by over 2,500 km, it shows that Neanderthals were a homogeneous species that was distinct from ancient humans. In fact, the differences in Genetic material found in mitochondria, the organelles that generate energy for the cell.mtDNA The order of nucleotides in a DNA or RNA molecule, or the order of amino acids in a protein molecule.sequences compared to modern humans were so great that calculations indicated that the last common ancestor between modern man and Neanderthal must have been at least 365,000-850,000 years ago.

Igor V. Ovchinnikov, I.V., A. Gotherstrom, G. P. Romanovak, V. M. Kharitonov, K. Liden, and W. Goodwin. 2000. Molecular analysis of Neanderthal Deoxyribonucleic acid: the chemical inside the nucleus of a cell that carries the genetic instructions for making living organisms.DNA from the northern Caucasus. Nature 404: 490-493.

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Little diversity among Neanderthals

Sequencing of a third Neanderthal specimen demonstrated that the three specimens were closely related (differing by only a few bases) although they were separated by over 1000 miles and died tens of thousands of years apart. Although the differences between modern humans and Neanderthals are large (>6%), the differences among individual humans or among individual Neanderthals is small compared to other apes (see table below). Such low genetic diversity among Neanderthals are consistent with a creation model in which Neanderthals were specially created as a small population in the relatively recent past. The much larger variation seen among chimpanzees and gorillas does not eliminate a creation model, but does indicate that those creatures were created well before modern humans.

Genetic material found in mitochondria, the organelles that generate energy for the cell.mtDNA Sequence Variation Among Species
Population Individuals Mean Minimum Maximum s.d.
Neanderthals 3 3.73 - - -
Humans 5,530 3.43 0.00 10.16 1.21
Chimpanzees  359 14.81 0.00 29.06 5.70
Gorillas 28 18.57 0.40 28.79 5.26

Krings, M., C. Capelli, F. Tschentscher, H. Geisert, S. Meyer, A. von Haeseler, K. Grossschmidt, G. Possnert, M. Paunovic, and S. P��bo. 2000. A view of Neandertal genetic diversity Nature Genetics 26: 144-146.

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Last updated January 2, 2001

 

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