On the Morphology of the Chromosomes in Gallinaceae

The present work has had for subject a morphological study of the following specimens of Gallinaceae: common fowl (Gallus domesticus), Caucasian pheasant (Phasianus colchicus), silver peasant (Nycthemerus argentatus), peacock (Pavo cristatus), guineafowl (Numidae meleagris), turkey (Melagris gallopavo), woodcock (Tetrao tetrix).The individuality of the largest elements of chromosome complements has been established for all these specimens; the corresponding caryograms are given in Figs. 2, 4, 6, 8, 10, 12, 14. The general aspect of the chromosome complement in each specimen can be respectively seen in Figs. 1, 3, 5, 7, 9, 11, 13, 15, 17, 19. Determination of the chromosome numbers has not been aimed at in the present research.2. The comparison of the individual chromosomes studied between themselves has revealed a similarity of a number of chromosomes. On the strength of morphological data and the length of chromosomes, a table has been drawn (Fig. 15). As a result, fourteen chromosome types have been ascertained in Gallinaceae (Fig. 16).3. The material obtained enables us to distinguish two groups of caryotypes; the first group, embracing common fowl, peacock guinea-fowl, is characterized by the presence of numerous chromosomes with two arms; the second group containing Caucasian pheasant, silver pheasant, turkey, stone partridge (according to data obtained by Peshkovskaia) is characterized by the prevalence of rod-shaped chromosomes with a terminal spindle fiber attachment.4. The strong similarity between the caryotypes of a number of large individual chromosomes of the specimens studied leads the authors to the conclusion that in the evolution of Gallinaceae the divergence of separate forms was in the main not followed by any morphological changes in chromosomes, being apparently due to mutations of genes.