I’ll do better: here are three related articles you can read yourself on-line. Hopefully this will satisfy your apparent intimation that I refuse to get into a detailed discussion of the subject with some internet troll who can’t be bothered to register. BTW: Where did this little cheap shot come from, Nosy? Have I EVER referenced something I can’t back up?
Chen L, DeVries AL, Cheng C-CH, 1997,
Evolution of antifreeze glycoprotein gene from a trypsinogen gene in Antarctic notothenioid fish PNAS 94: 3811—3816
Chen L, DeVries AL, Cheng C-CH, 1997
Convergent evolution of antifreeze glycoproteins in Antarctic notothenioid fish and Arctic cod, PNAS 94: 3817—3822
Hsiao K, Cheng C-CH, Fernandes IE, Detrich HW, and DeVries AL, 1990,
An antifreeze glycopeptide gene from the antarctic cod Notothenia coriiceps neglecta encodes a polyprotein of high peptide copy number PNAS 87: 9265—9269
Here’s a few additional abstracts that bolster the trypsinogen => AFGP transition which examine related notothenioid fishes in near-Antarctic and Antarctic waters:
Cheng CH, Chen L, Near TJ, Jin Y, 2003, Functional antifreeze glycoprotein genes in temperate-water New Zealand nototheniid fish infer an Antarctic evolutionary origin, MolBioEvo 20: 1897-1908
quote:
The fish fauna of the Antarctic Ocean is dominated by five endemic families of the Perciform suborder Notothenioidei, thought to have arisen in situ within the Antarctic through adaptive radiation of an ancestral stock that evolved antifreeze glycoproteins (AFGPs) enabling survival as the ocean chilled to subzero temperatures. The endemism results from geographic confinement imposed by a massive oceanographic barrier, the Antarctic Circumpolar Current, which also thermally isolated Antarctica over geologic time, leading to its current frigid condition. Despite this voluminous barrier to fish dispersal, a number of species from the Antarctic family Nototheniidae now inhabit the nonfreezing cool temperate coasts of the southern continents. The origin of these temperate-water nototheniids is not completely understood. Since the AFGP gene apparently evolved only once, before the Antarctic notothenioid radiation, the presence of AFGP genes in extant temperate-water nototheniids can be used to infer an Antarctic evolutionary origin. Genomic Southern analysis, PCR amplification of AFGP genes, and sequencing showed that Notothenia angustata and Notothenia microlepidota endemic to southern New Zealand have two to three AFGP genes, structurally the same as those of the Antarctic nototheniids. At least one of these genes is still functional, as AFGP cDNAs were obtained and low levels of mature AFGPs were detected in the blood. A phylogenetic tree based on complete ND2 coding sequences showed monophyly of these two New Zealand nototheniids and their inclusion in the monophyletic Nototheniidae consisted of mostly AFGP-bearing taxa. These analyses support an Antarctic ancestry for the New Zealand nototheniids. A divergence time of approximately 11 Myr was estimated for the two New Zealand nototheniids, approximating the upper Miocene northern advance of the Antarctic Convergence over New Zealand, which might have served as the vicariant event that lead to the northward dispersal of their most recent common ancestor. Similar secondary northward dispersal likely applies to the South American nototheniid Paranotothenia magellanica, which has four AFGP genes in its DNA, but not to the sympatric nototheniid Patagonotothen tessellata, which does not appear to have any AFGP sequences in its genome at all.
Bargelloni L, Ritchie PA, Patarnello T, Battaglia B, Lambert DM, Meyer A, 1994, Molecular evolution at subzero temperatures: mitochondrial and nuclear phylogenies of fishes from Antarctica (suborder Notothenioidei), and the evolution of antifreeze glycopeptides MolBioEvo 11:854-863
quote:
Most fishes of the perciform suborder Notothenioidei are endemic to the subzero marine waters of Antarctica. A number of remarkable physiological attributes allow them to inhabit this extreme environment; for example, the blood of almost all notothenioid species contains antifreeze glycopeptides. To establish a molecular phylogenetic hypothesis for these fishes, DNA sequences from two mitochondrial genes, portions of the 12S and 16S ribosomal genes (928 base pairs [bp]), were determined for 18 species. These belong to 15 genera in five families of the suborder. The DNA data suggest that two of these families are unnatural groups and consequently that the classification and phylogeny of this suborder is in need of revision. In terms of DNA variation, the Bovichtidae are a distantly related sister group to the other families of the suborder that includes the icefishes, the only vertebrates without hemoglobin. The fishes of the suborder (except the Bovichtidae) seem to have speciated rapidly, forming an adaptive radiation in the Antarctic waters. A phylogenetic analysis of published hemoglobin amino acid sequences for other notothenioid fishes supports these results from mtDNA. On the basis of molecular phylogeny, the evolution of antifreeze glycopeptides was studied. The age of the radiation of notothenioid fishes had been estimated to be at least 38 Mya. However, the level of mtDNA variation detected in notothenioid fishes appears to be too low to agree with this date of origin and might instead suggest a younger age (10-15 Mya). Alternatively, the low level of detected mtDNA variation would agree with the traditional old-age estimate if an extremely slow rate of mtDNA evolution is postulated for this group. This slow-rate hypothesis, if true, could be explained by decreased metabolic rates slowing down the tempo of molecular evolution.
What a waste of time on a Welcome Visitor’s thread, especially posting all this to someone who’s apparently unwilling to even register on the site. Satisfied, Nosy, or do you want me to buy you a subscription to Nature so you can get the original article yourself instead of "trotting off to the library for a specific point"?
It'll be interesting to hear what your reasons for creationism are (hope oft springs eternal that someone will come up with a new argument, or a new twist on an old one.) Looking forward to discussing with you.
™ Version 4.2