tetraploid animals

Janice M. Glime jmglime at MTU.EDU
Fri Oct 1 16:02:44 EST 1999

Dear Plant-edders,
  That rat might be the first tetraploid mammal, but I don't think it is
the first evidence of tetraploidy in animals.  Fish are much like plants
in that fertilization is external.  This provides a much greater
opportunity for hybridization.  I have a vague recollection of this being
true in Salmonids, so I asked our fish biologist.  Here is his offering on
the subject.

> I thought I remembered that also about the salmonids so I did a quick
> search to confirm it.  From the sounds of the abstract that I copied below,
> it must contain references that document tetraploidy in the salmonids.
> Once again, it sounds like fish win another round in the interesting
> diversity game.  That is until the plants and insects join the contest!
> -Casey
> TITLE: Sequence of sockeye salmon type 1 and 2 growth hormone genes 
>                     and the relationship of rainbow trout with Atlantic and 
>                     Pacific salmon.
>             AUTHOR: Devlin, R. H.
>       AUTHOR AFFIL: Dep. Fisheries and Oceans, 4160 Marie Dr., West
> Vancouver, BC 
>                     V7V 1N6
>            COUNTRY: CAN
>       SOURCE TITLE: Canadian Journal of Fisheries and Aquatic Sciences
>             SOURCE: 50, no. 8 (1993): 1738-1748 
>      DOCUMENT TYPE: Article
>        STANDARD NO: 0706-652X
>               YEAR: 1993
>           LANGUAGE: English (EN)
>         SUMMARY LA: English (EN); French (FR)
>           ABSTRACT: Two types of growth hormone genes have been isolated from 
>                     sockeye salmon (Oncorhynchus nerka) and their complete 
>                     nucleotide sequence determined. The genes encode
> proteins of 
>                     210 amino acids and show considerable similarity to
> growth 
>                     hormones characterized in other salmonids and fishes.
> The two 
>                     genes presumably arose from a gene duplication event that 
>                     generated the tetraploid condition in salmonids and are 
>                     highly conserved in their coding regions. The sequences
> have 
>                     diverged approximately 18% in noncoding regions since the 
>                     gene duplication event and show numerous deletions and/or 
>                     insertions. Isolation of these two genes from a Pacific 
>                     salmon allows comparison of their sequences to growth
> hormone 
>                     genes characterized from rainbow trout and from Atlantic 
>                     salmon. The results indicate that rainbow trout is more 
>                     similar to Pacific than to Atlantic salmon and suggest
> that 
>                     Atlantic salmon diverged from Pacific salmonids at a time 
>                     when sockeye and rainbow trout were part of a common
> breeding 
>                     population. These results support the recent
> reclassification 
>                     of rainbow trout from the genus Salmo to Oncorhynchus.
>        MAJ CONCEPT: Biochemistry and Biophysics; Endocrine System; Genetics; 
>                     Methodology; Reproductive System
>         SUPER TAXA: Osteichthyes: Pisces, Vertebrata, Chordata, Animalia
>         TAXA NOTES: animals; chordates; fish; nonhuman vertebrates;
> vertebrates
>           ORGANISM: Oncorhynchus nerka (Osteichthyes); Osteichthyes 
>                     (Osteichthyes); Salmo (Osteichthyes)
>           SEQ DATA: molecular sequence data; nucleotide sequence
 Janice M. Glime, Professor  
 Department of Biological Sciences
 Michigan Technological University
 Houghton, MI 49931-1295
 jmglime at mtu.edu
 FAX 906-487-3167 

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