Monophyletic origin and unique dispersal patterns of domestic fowls.

With the aim of elucidating in greater detail the genealogical origin of the present domestic fowls of the world, we have determined mtDNA sequences of the D-loop regions for a total of 21 birds, of which 12 samples belong to red junglefowl (Gallus gallus) comprising three subspecies (six Gallus gallus gallus, three Gallus gallus spadiceus, and three Gallus gallus bankiva) and nine represent diverse domestic breeds (Gallus gallus domesticus). We also sequenced four green junglefowl (Gallus varius), two Lafayette's junglefowl (Gallus lafayettei), and one grey junglefowl (Gallus sonneratii). We then constructed a phylogenetic tree for these birds by the use of nucleotide sequences, choosing the Japanese quail (Coturnix coturnix japonica) as an outgroup. We found that a continental population of G. g. gallus was the real matriarchic origin of all the domestic poultries examined in this study. It is also of particular interest that there were no discernible differences among G. gallus subspecies; G. g. bankiva was a notable exception. This was because G. g. spadiceus and a continental population of G. g. gallus formed a single cluster in the phylogenetic tree. G. g. bankiva, on the other hand, was a distinct entity, thus deserving its subspecies status. It implies that a continental population of G. g. gallus sufficed as the monophyletic ancestor of all domestic breeds. We also discussed a possible significance of the initial dispersal pattern of the present domestic fowls, using the phylogenetic tree.

Specific activation in jun-transformed avian fibroblasts of a gene (bkj) related to the avian beta-keratin gene family.

We have analyzed differential gene expression in normal versus jun-transformed avian fibroblasts by using subtracted nucleic acid probes and differential nucleic acid hybridization techniques for the isolation of cDNA clones. One clone corresponded to a gene that was strongly expressed in a previously established quail (Coturnix japonica) embryo fibroblast line (VCD) transformed by a chimeric jun oncogene but whose expression was undetectable in normal quail embryo fibroblasts. Furthermore, the gene was expressed in quail or chicken fibroblast cultures that were freshly transformed by retroviral constructs carrying various viral or cellular jun alleles and in chicken fibroblasts transformed by the avian retrovirus ASV17 carrying the original viral v-jun allele. However, its expression was undetectable in a variety of established avian cell lines or freshly prepared avian fibroblast cultures transformed by other oncogenes or a chemical carcinogen. The nucleotide and deduced amino acid sequences of the cDNA clone were not identical to any sequence entries in the data bases but revealed significant similarities to avian beta-keratin genes; the highest degree of amino acid sequence identity was 63%. The gene, which we termed bkj, may represent a direct or indirect target for jun function.

The genetic link between the Chinese bamboo partridge (Bambusicola thoracica) and the chicken and junglefowls of the genus Gallus.

Further comparison of mitochondrial control-region DNA base sequences of 16 avian species belonging to the subfamily Phasianinae revealed the following: (i) Generalized perdicine birds (quails and partridges) are of ancient lineages. Even the closest pair, the common quail (Coturnix coturnix japonica) and the Chinese bamboo partridge (Bambusicola thoracica), maintained only 85.71% identity. (ii) The 12 species of phasianine birds previously and presently studied belonged to three distinct branches. The first branch was made exclusively of members of the genus Gallus, while the second branch was made of pheasants of the genera Phasianus, Chrysolophus, and Syrmaticus. Gallopheasants of the genus Lophura were distant cousins to these pheasants. The great argus (Argusianus argus) and peafowls of the genus Pavo constituted the third branch. The position of peacock-pheasants of the genus Polyplectron in the third branch was similar to that of the genus Lophura in the second branch. Members of the fourth phasianine branch, such as tragopans and monals, were not included in the present study. (iii) The one perdicine species, Bambusicola thoracica, was more closely related to phasianine genera Gallus and Pavo than to members of other perdicine genera. The above might indicate that Bambusicola belong to one-stem perdicine lineage that later splits into two sublineages that yielded phasianine birds, one evolving to Gallus, and the other differentiating toward Pavo and its allies.