Daniel Smith
Posts: 970
Joined: Sep. 2007
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| Quote (mitschlag @ Mar. 01 2008,03:52) | | Quote (Daniel Smith @ Feb. 29 2008,20:11) | Both of these papers advance a saltational mechanism for evolution, similar to what Schindewolf proposed. That such mechanisms require far fewer transitional steps than the gradualism Darwin proposed is IMO vindication for Schindewolf. If these karyotypic changes resulted in morphological changes, these transitional steps would be next to invisible in the fossil record - thus explaining Schindewolf's gaps between types.
From Kinetochore reproduction in animal evolution: Cell biological explanation of karyotypic fission theory:
<snip>
From Karyotypic fissioning and Canid phylogeny: |
You pays your money and you takes your choice.* Try this one on for size:
A test of the karyotypic fissioning theory of primate evolution
| Quote | Stanyon R.
Karyotypic fissioning theory has been put forward by a number of researchers as a possible driving force of mammalian evolution. Most recently, Giusto and Margulis (BioSystems, 13 (1981) 267-302) hypothesized that karyotypic fissioning best explains the evolution of Old World monkeys, apes, and humans. According to their hypothesis, hominoid karyotypes were derived from the monkey chromosome complement by just such a fissioning event. That hypothesis is tested here by comparing the G-banded chromosomes of humans and great apes with eight species of Old World monkeys. Five submetacentric chromosomes between apes and monkeys have identical banding patterns and nine chromosomes share the same pericentric inversion. Such extensive karyological similarities are not in accordance with, or predicted by karyotypic fissioning. Apparently, karyotypic fissioning is an extremely uneconomical model of chromosomal evolution. The strong conservation of banding patterns sometimes involving the retention of identical chromosomes indicates that ancient linkages of genes have probably been maintained through many speciation events. |
(Emphasis added)
*Cherry-picking the literature is a favored Creationist tactic. |
Here's the paper they refer to:
Karyotypic fission theory and the evolution of old world monkeys and apes.
link
Abstract: | Quote | | The karyotypes of living catarrhines are correlated with the current concepts of their fossil record and systematic classification. A phylogeny, beginning at the base of the Oligocene, for those animals and their chromosome numbers is presented. Todd's (1970) theory of karyotypic fissioning is applied to this case - three fissioning events are hypothesized. A late Eocene event (the primary catarrhine fissioning) is hypothesized to underlie the diversification of the infraorder Catarrhini into its extant families, the second fissioning underlies the radiation of the pongidae/Hominidae in the Miocene and the third accounts for the high chromosome numbers (54 - 72) and the Neogene(Miocene-Pliocene-Pleistocene) radiation of members of the genus Cercopithecus. Published catarrhine chromosome data, including that for "marked" chromosomes (those with a large achromatic region that is the site for ribosomal RNA genes) are tabulated and analysed. The ancestral X chromosome is always retained in the unfissioned metacentric state. The Pongidae/Hominidae have 15 pairs of mediocentric chromosomes that survived the second fissioning whereas the other chromosomes (besides the X) are thought to be fission-derived acrocentrics. Both the detailed karyology and the trend from low to high numbers is best interpreted to support Todd's concept of adaptive radiations correlated with karyotypic fissioning in ancestral populations. |
So I guess the jury's still out on this one.
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"If we all worked on the assumption that what is accepted as true is really true, there would be little hope of advance." Orville Wright
"The presence or absence of a creative super-intelligence is unequivocally a scientific question." Richard Dawkins
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