October
18, 1985
Dear
Mr Plant:
After
re-reading some of your material I wrote to Mrs Banning regarding references
to fertile second and third generation Avian Hybrids. Her reply is enclosed. I’m
afraid some well meaning, highly respected individuals may have been making
comments based upon phenotypic observation rather than sound genetic evidence
- but then that may be only my opinion too. At any rate, a copy of her replay
is attached (#1).
I
told Dr Bitgood of your interest in his reading and he commented as shown in
attachment (#2).
Best
of luck,
John
L.Skinner
Professor (Emeritus)
Memo
to: John Skinner
From: Jim Bitgood
October
15, 1985
In
response to our conversation of several weeks ago in regard to the possible
monophyletic origin of our domestic fowl from Gallus
gallus (Red Jungle Fowl), the following information is provided.
Weiss
and Briggs (1972) found that the Red Jungle Fowl carried a genetically
transmitted viral genome of subgroup E specificity that was indistinguishable
from that found in domesticated chickens.
Frisby
et al. (1979) reported that domesticated chickens
carry the genome of the endogenous retrovirus RAV-O as DNA sequences that were
integrated into the host chromosomes and transmitted through the cell line.
Molecular hybridization of RAV-O cDNA showed 80% homology in the genomes of
the domestic chicken and the Red Jungle Fowl. G. sonnerati (Grey Jungle Fowl),
G. varius (Green Jungle Fowl), ring necked pheasant and Japanese quail all
showed less than 10% homology. Further, restriction enzyme digests showed
several distinct fragments of DNA hybridization to chick retrovirus cDNA in
both the Red Jungle Fowl and domestic chicken, however no fragments related to
the chicken retrovirus were found in the Grey, Green or Ceylonese Jungle Fowl
(G. lafayettei). The authors theorize that the RAV-O retrovirus was introduced
into the Red Jungle Fowl after speciation occurred, but before domestication,
probably within the last million years.
Of
further interest, using molecular hybridization on chicken chromosomes,
Tereba et al. (1981) showed that the ev-2 locus, which codes for the
prototype RAV-O genome, is in the middle of the long arm of chromosome 2.
References
Frisby,
D.P, R.A. Weiss, M. Roussel, and D. Stehelin, 1979. The distribution of
endogenous chicken retrovirus sequences in the DNA of Galliform birds does not
coincide with avian phylogenetic relationships. Cell 17:623-634.
Tereba,
A., L.B. Crittenden, and S. M. Astrin, 1981, Chromosomal localization of three
endogenous retrovirus loci associated with virus production in White Leghorn
chickens. J. Virology 39:282-289.
Weiss,
R.A. and P.M. Briggs, 1972. Leukosis and Marek’s disease viruses of feral
Red Jungle Fowl and domestic fowl in Malaya. J. Natl. Cancer Inst.
49:1713-1725.