Colour Pattern Polymorphism Research Articles

Natural Selection and the Maintenance of Colour Pattern Polymorphism in the Australian Plague Locust Chortoicetes terminifera

Twelve samples of C. termini/era from seven locations in eastern Australia were analysed for colour pattern polymorphism. Although there was heterogeneity between the samples the overall frequencies of the colour pattern genotypes were very similar. Males and females showed consistent differences in their genotype frequencies and this is presumed to reflect differential selection between the two sexes. A comparison between observed genotype frequencies and those expected under random mating and in the absence of selection revealed large differences. In particular, genotypes heterozygous for two dominant genes were consistently underrepresented. While these differences could result from non-random mating it is argued that they are more likely to be due to viability differences between the genotypes.

Relationships of the Baja California Ground Snakes, Genus Sonora

Sonora bancroftae Klauber, 1943, and S. mosaueri Stickel, 1938, are placed in the synonymy of S. semiannulata Baird and Girard, 1853. The characters that have been used to separate these taxa (color pattern, numbers of ventrals and subcaudals, and dorsal scale row reduction pattern) are shown to be insufficient for that purpose. Three species of Sonora presently are recognized as occurring in Baja California, M6xico, and the adjacent United States. S. bancroftae Klauber, 1943 (type locality: 2 mi. E San Jorge, Baja California Norte), is found in northwestern Baja California, and S. mosaueri Stickel, 1938 (type locality: Comondfi, Baja California Sur), is found in the southern half of Baja California. S. semiannulata Baird and Girard, 1853 (type locality: Sonora, restricted by Stickel, 1943, to the vicinity of the Santa Rita Mountains of southern Arizona, United States) is found in the southwestern quadrant of the United States and northern mainland Mexico, but in Baja California occurs only in the northeastern part, northward from the vicinity of Santa Rosalia (Stickel, 1943; Stebbins, 1966). These species have not been reviewed since Stickel (1938, 1943). In the intervening years, several specimens have been collected that improve our understanding of the relationships of these ground snakes. As first revised by Stickel (1938), the Sonora semiannulata complex (all Sonora except S. aemula and S. michoacanensis) contained five species: S. taylori (South Texas), S. episcopa (Great Plains), S. mosaueri (Baja California), S. semiannulata (western United States), and S. miniata (Idaho south to Arizona and California). The features used to diagnose these phenetically very similar species were temporal formula (1+1 in S. taylori and 1+2 in all others), numbers of ventrals and subcaudals, numbers of dorsal scale rows, and color pattern. Although Stickel was aware of color pattern polymorphism in S. episcopa and in S. semiannulata in the eastern part of its range, he distinguished western S. semiannulata from the largely sympatric

Genetics of color pattern polymorphism in the California kingsnake

The California kingsnake, Lampropeltis getulus californiae, exhibits polymorphic variation in color pattern inherited in simple Mendelian fashion. The ubiquitous ringed pattern is recessive to the geographically restricted striped, with the degree of dominance (purity of striping) evidently influenced by modifiers. A geographically more restricted pattern, Long Beach, apparently is due to a third allele at the same locus. A fourth pattern type, Whittier, is the ringed morph with a melanistic dorsal suffusion and black ventral surface. It is known not to be dominant to ringed, but further details remain to be elucidated. Wholly black ventral coloration in striped snakes is inferred to be due to a recessive gene closely linked with the dominant gene for striping.

Protein Electrophoresis and the Systematics of some New Guinea Hylid Frogs (Genus Litoria)

Dessauer, H. C., D. F. Gartside, and R. G. Zweifel (Department of Biochemistry, Louisiana State University School of Medicine, New Orleans, LA 70112, and Department of Herpetology, American Museum of Natural History, New York, NY 10024) 1977. Protein electrophoresis and the systematics of some New Guinea hylid frogs (genus Litoria). Syst. Zool. 26:426–436.—Samples of 13 nominal species of the more than 50 recorded from New Guinea were collected at eight localities. Comparative data from nine proteins studied in all species indicate wide biochemical divergence among species, in concordance with morphological evidence, and suggest the presence of two distinct lineages. Biochemical evidence supports the recognition of two previously described pairs of sibling species and suggests that a third cryptic species may exist in one of these pairs. Litoria infrafrenata, a series for which no morphological variation of consequence in New Guinea has been recorded, shows population differentiation in proteins. Parameters of genetic variation in the species were estimated as: Ā = 1.62, P = 0.50, H = 0.073. In contrast, L. iris, a species with marked color pattern polymorphism, shows little variation in proteins. [Electrophoresis; Hylidae; Litoria.]

Origin of Pigment Cells from the Neural Crest in the Mouse Embryo

testing the pigment-forming potency of various portions of mouse embryos of a potentially pigmented (black) strain, evidence was obtained which suggested that the migratory pigment-forming cells, the melanophores, take their origin from the neural crest, as in other vertebrates, e.g., amphibians and birds.The results of grafting a variety of embryonic mouse tissues, such as skin ectoderm plus the underlying mesoderm, somites with and without the adjacent neural tube, limb buds and prospective limb buds, from various body levels, showed