mitschlag
Posts: 236 Joined: Sep. 2006
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Quote (JAM @ Mar. 02 2008,18:47) | Quote (Daniel Smith @ Mar. 02 2008,12:40) | Quote (JAM @ Mar. 01 2008,22:10) | Quote (Daniel Smith @ Mar. 01 2008,21:46) | Quote (JAM @ Mar. 01 2008,11:18) | Schindewolf's hypothesis was about MORPHOLOGICAL saltation. Can't you read and comprehend the adjective CHROMOSOMAL?
Did Schindewolf even mention chromosomes in his Bib--er, book? |
Yes, in notes 21 and 22 on pages 349 and 352 where he speaks of Goldschmidt's Systemmutationen. On page 352 he says: Quote | This repatterning, or Systemmutation, is attributed to cytologically provable breaks in the chromosomes, which evoke inversions, duplications, and translocations. A single modification of an embryonic character produced in this way would then regulate a whole series of related ontogenetic processes, leading to a completely new developmental type. (his emphasis) |
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Schindewolf was wrong.
The point you keep missing is that these karyotypically visible events (fission, fusion, inversion, translocation, etc.) can produce speciation with absolutely zero change in phenotype.
On the other hand, a single nucleotide substitution can cause massive phenotypic changes.
Can you manage to wrap your brain around that fundamental point? |
I'm aware of the former,... |
Since you know he was wrong about that, why would you claim that he was vindicated? Quote | ...but can you give me examples of the latter? |
Yes; oligodontia, orofacial cleft, optic atrophy, absence of radius, radioulnar synostosis, absence of thumbs, chondrodysplasia, GH insensitivity, split-hand/foot malformation with long bone deficiency, etc. |
Remember this?
-------------------------------------------------------------------------------- Science 6 April 2007: Vol. 316. no. 5821, pp. 112 - 115
Quote | A Single IGF1 Allele Is a Major Determinant of Small Size in Dogs
The domestic dog exhibits greater diversity in body size than any other terrestrial vertebrate. We used a strategy that exploits the breed structure of dogs to investigate the genetic basis of size. First, through a genome-wide scan, we identified a major quantitative trait locus (QTL) on chromosome 15 influencing size variation within a single breed. Second, we examined genetic variation in the 15-megabase interval surrounding the QTL in small and giant breeds and found marked evidence for a selective sweep spanning a single gene (IGF1), encoding insulin-like growth factor 1. A single IGF1 single-nucleotide polymorphism haplotype is common to all small breeds and nearly absent from giant breeds, suggesting that the same causal sequence variant is a major contributor to body size in all small dogs. |
-------------- "You can establish any “rule” you like if you start with the rule and then interpret the evidence accordingly." - George Gaylord Simpson (1902-1984)
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