Skin color variation in eastern Nepal

The purpose of this paper is to provide skin color data on several endogamous groups of eastern Nepal and to demonstrate genetic microdifferentiation in skin color. Skin reflectance measures were taken at the upper inner arm and forehead sites, using the British DSL Model 99 Reflectance Spectrophotometer fitted with blue, green, and red filters. Measurements on 484 males representing six endogamous groups (Jirel, Sunwar, Sherpa, Tamang, Brahman, Chetri) were utilized. After adjusting for group-specific age effects, multivariate likelihood ratio permutation tests were used to assess ethnic differences in skin reflectance means and covariance matrices. Ethnic group membership had a highly significant effect on skin color at the upper inner arm site and at the forehead site. Differential tanning responses among groups were also detected and may represent the influence of genotype-environment interaction on reflectance traits. Mahalanobis distance analysis revealed patterns of microdifferentiation that are inconsistent with oral historical accounts. Little support was found for the ethnohistorical belief that Jirels are a hybrid group descended from Sunwars and Sherpas, even though this scenario is supported by linguistic, anthropometric, and dermatoglyphic data. We suggest that while reflectometric studies of skin pigmentation may be useful in assessing the macrodifferentiation of human populations, the use of skin color in differentiation studies at the local population level needs to be carefully evaluated.     

Allozyme variation in the solanaceous fruit fly Bactrocera latifrons (insecta: diptera: tephritidae) from peninsular malaysia

• 1.1. Bactrocera latifrons fruit flies recovered from four solanaceous fruits (Capsicum annuum, Lycopersicon esculentum, Solanum pseudocapsicum and Solanum melongena) in Peninsular Malaysia were analyzed for a total of 15 gene-enzyme systems comprising 21 loci.
• 2.2. Eleven loci—aAdh, Aldox, Ald, Est-F, Est-S, Hk-F, Ldh, cMdh, Me, Pep-A and Pep-C—were invariant.
• 3.3. Of the polymorphic loci, cathodal alcohol dehydrogenase, glucose phosphate isomerase, glycerol-3-phosphate dehydrogenase, hydroxybutyrate dehydrogenase, isocitrate dehydrogenase, anodal malate dehydrogenase and phosphoglucomutase were represented by two alleles each, while hexokinase-S, peptidase-B and phosphogluconate dehydrogenase were represented by three alleles each.
• 4.4. The proportion of polymorphic loci ranged from 0.28 to 0.33, while the mean heterozygosity ranged from 0.04 to 0.13.
• 5.5. The genetic variability is associated with the host range.

     

Allozyme variation in a dimeric esterase of the oriental fruit fly,Dacus dorsalis (insecta: tephritidae), from peninsular malaysia

• 1.1. Seven natural populations of Dacus dorsalis were analyzed for a dimeric esterase by means of horizontal starch-gel electrophoresis.
• 2.2. The electrophoretic phenotypes were governed by nine codominant Est-D alleles.
• 3.3. The commonest allele in all seven population samples was Est-D¹⁰⁰ which encoded an electrophoretic band with intermediate mobility.
• 4.4. The distribution of EST-D phenotypes were in accordance with Hardy-Weinberg expectations.
• 5.5. There was no geographic variation in the distribution of Est-D alleles.

     

Morphological and allozyme studies of small terrestrial snails (Opeas sp., Subulina sp., and Huttonella bicolor) collected from peninsular malaysia

Shell morphological characters and allozyme electrophoresis were used to study the relationships among six geographical populations of land snails collected from Peninsular Malaysia. Allozyme electrophoresis was used to study the genetic variations to complement the morphological features studied that included shell lengths, numbers of whorls and shell colour. Ten loci coding for six enzymes (MDH, LAP, ALP, PGM, G6P DH, and EST) could be reliably scored in samples from the six populations studied. The dendrogram showed two major clusters with one cluster comprising Subulinidae populations from Perak, Selangor, Johor, Terengganu, and Pahang while the other cluster included only the Streptaxidae Huttonella bicolor (red) population. The Subulinidae populations were grouped into two subclusters: one subcluster included the Subulina sp. populations from Perak, Selangor, and Johor, while the other subcluster included the Opeas sp. populations from Terengganu and Pahang. Morphological features can identify the different families ant therefore they can complement the allozyme genetic studies on the land snail populations. Like other reports in the literature, our results also underline the importance of a genetic approach in conjunction with a morphological approach, for discriminating land snail species. The present results suggest that small land snails, which were similar in colour but different in sizes, were not of the same family/genus. The text was submitted by the authors in English.     

Nonmetric cranial trait variation and population history of medieval east slavic tribes

The population history of the East Slavs is complicated. There are still many unanswered questions relating to the origins and formation of the East Slavic gene pool. The aims of the current study were as follows: (1) to assess the degree of biological affinity in medieval East Slavic tribes and to test the hypothesis that East Slavic peoples have a common origin; (2) to show their genetic connections to the autochthonous populations of the northern part of Eastern Europe (Baltic and Finno‐Ugric tribes); and (3) to identify a genetic continuity between the bearers of Chernyakhov culture and medieval Eastern Slavs. In this study, nonmetric cranial trait data for medieval East Slavic tribes and comparative samples from unrelated groups were examined. Analyzes of phenotypic differentiation were based on Nei's standard genetic distance and hierarchical G_ST statistics. The results obtained suggest that the genetic affinity of the East Slavic tribes is due not only to inter‐tribal gene flow, but is, more importantly, a result of their common population history. Evidence of gene flow from the Baltic and Finno‐Ugric groups was showed in the gene pool of Eastern Slavs, as was genetic continuity between medieval East Slavic tribes and the populations of the preceding Chernyakhov culture. These findings support a “generalizing” hypothesis of East Slavic origin, in which a Slavic community was formed in some particular ancestral area, and subsequently spread throughout Eastern Europe. Am J Phys Anthropol 152:495–505, 2013. © 2013 Wiley Periodicals, Inc.     

Flagellar variation in Serratia marcescens is associated with color variation.

The pigmented enterobacterium Serratia marcescens, an opportunistic pathogen, shows a striking variation of its red color. Different strains differ greatly both in color and in the frequency with which they produce color variants. Within a strain, the variations occur at constant rates and are reversible. During an investigation of this phenomenon we observed that variation of a 39-kilodalton protein in S. marcescens 274 is closely associated with color variation. Using antibodies to this protein we identified it as being a component of the bacterial flagella. Variation of surface proteins often provides an organism with alternate offense-defense strategies for survival in a challenging environment. The pigment, in association with flagella, may provide such a function for S. marcescens.     

Meat-eating behaviour in wild orang utans,Pongo pygmaeus

Meat-eating was observed for the first time among a population of wild orang utans at Gunung Leuser National Park, Sumatra. An adult female who was consorting with an adult male consumed a gibbon (Hylobates lar) carcass. There was no food sharing between the consort pair. The absence of food sharing is interpreted as indicative of the anti-social attitude of adult orang utans.     

Skin and hair pigmentation variation in Island Melanesia

Skin and hair pigmentation are two of the most easily visible examples of human phenotypic variation. Selection-based explanations for pigmentation variation in humans have focused on the relationship between melanin and ultraviolet radiation, which is largely dependent on latitude. In this study, skin and hair pigmentation were measured as the melanin (M) index, using narrow-band reflectance spectroscopy for 1,135 individuals from Island Melanesia. Overall, the results show remarkable pigmentation variation, given the small geographic region surveyed. This variation is discussed in terms of differences between males and females, among islands, and among neighborhoods within those islands. The relationship of pigmentation to age, latitude, and longitude is also examined. We found that male skin pigmentation was significantly darker than females in 5 of 6 islands examined. Hair pigmentation showed a negative, but weak, correlation with age, while skin pigmentation showed a positive, but also weak, correlation with age. Skin and hair pigmentation varied significantly between islands as well as between neighborhoods within those islands. Bougainvilleans showed significantly darker skin than individuals from any other island considered, and are darker than a previously described African-American population. These findings are discussed in relation to prevailing hypotheses about the role of natural selection in shaping pigmentation variation in the human species, as well as the role of demographic processes such as admixture and drift in Island Melanesia.     

Foliage color contrasts and adaptive fruit color variation in a bird-dispersed plant community

The color of vertebrate-dispersed fruits has been a source of inquiry for over 150 years, yet the ecological and evolutionary processes responsible for fruit color diversity remain elusive. We tested the hypothesis that fruit color varies temporally, to maximize conspicuousness against seasonal changes in foliage coloration, in a bird-dispersed plant community in western North America. Field observations showed that while red fruits predominate during summer periods of green foliage coloration, black fruits are produced during flushes of red-orange foliage coloration in autumn. Although two species did not conform to this pattern, one produced its own contrasting background color, via colored bracts. We conducted experimental manipulations of both fruit color and the color of artificial backgrounds to test whether both factors had a synergistic effect on fruit removal rates. Interactions between fruit and background color explained most of the variation in experimental fruit removal rates. Although red fruits were removed rapidly on green backgrounds, preference for black fruits on red-orange backgrounds was less pronounced. Consequently, the temporal pattern in fruit color appears to result from elevated fruit conspicuousness against seasonal changes in foliage coloration. Support for this hypothesis suggests a temporal connection between fruit color diversity, foliage color contrasts and avian color preferences.     

花色素苷生物合成及花色的调控

近年来,花色研究工作备受关注。对于园艺学来说,要培育出自然界中原本没有的新颖花色,很有必要弄清控制花色形成的各种因素。随着分子生物学技术的迅速发展,对花色形成机制的研究已经深入到分子水平,本文主要介绍了花色素的合成与转运、液泡pH值、辅助色素和金属离子对花色的调控。     

Skin color comparisons among ethnic groups of college men

Reflectance readings of skin color were taken on the medial aspect of the left upper arm. The subjects were United States college men between ages 18 and 27 years attending the University of South Carolina. Using the DSL 99 Reflectance Spectrophotometer, readings were obtained under controlled conditions at five settings (601, 603, 605, 607, 609). Ethnic groups studied included young men of 1) Northwest European White ancestry, 2) West African Black ancestry, and 3) Afro-Black/Amerind ancestry. Means and variability statistics serve to describe the skin color distributions. Means were near 12 and 32 for filters 601 and 609 on men of West African Black ancestry, with corresponding means near 36 and 64 on men of Northwest European White ancestry. There was no overlapping of comparable frequency distributions from these two ethnic groups. Significance tests at P = .01 allowed acceptance of the hypothesis that skin color on the medial arm surface was darker for young men of Afro-Black ancestry than for those of 75% Afro-Black ancestry and 25% Amerind ancestry. Means from original data were compared with means from earlier studies on black and white males in Africa, America, and Europe.     

Skin color in the squids Loligo pealii and Loligo opalescens

Summary Rapid, physiological color changes seen in the skin of cephalopods are due to a unique anatomical system composed of chromatophore organs and iridophores. The morphology and ultrastructure of the chromatophores was studied in the squids Loligo pealii Lesueur and Loligo opalescens Berry. A three-dimensional model of a brown chromatophore was reconstructed from serial sections for the electron microscope.The chromatophore organ is composed of a central nucleated pigment cell, 10–30 obliquely striated muscle cells (radially arranged on the equator of the pigment cell), axons, Schwann cells, and sheath cells. The pigment cell consists of a central aggregation of pigment granules and surrounding peripheral cytoplasmic compartments. These regions are incompletely separated by an electron-dense, sac-like structure, the pigment container. Proximal portions of a muscle cell contact the pigment cell in regions called myo-chromatophore junctions. Neuromuscular and myo-muscular junctions are also present.The results presented are discussed in terms of previous morphological and physiological studies of chromatophores.Part of a study submitted in partial fulfillment of the requirement for the degree of Ph. D. (Anatomy), the Graduate School of Basic Medical Sciences, New York Medical College, New York, N.Y. 10029.The research reported here was in part supported by grants from the Health Research Council of the City of New York (U-1008) and United States Public Health Service, General Research Grant No. FR-05398.Report on some of this material was given at the Annual Meeting of the American Association of Anatomists, Philadelphia, Pennsylvania, April 19–22, 1971.     

Geographic variation in color of the synanthropic Blue rock pigeon

Variation in plumage color was studied in 211 populations of the blue rock pigeon (Columbia livia) from various geographic zones. The frequency distribution of three common and three rare phenotypes and an interspecific hybridization zone of C. livia and C. rupestris were described. Different conditions of the origin of the urban populations of blue rock pigeon and consequent high genetic heterogeneity of this species were revealed. The key aspect of color polymorphism in blue rock pigeon is synanthropization, i.e., anthropogenic evolution.     

Genetic basis of sex-specific color pattern variation in Drosophila malerkotliana

Pigmentation is a rapidly evolving trait that can play important roles in mimicry, sexual selection, thermoregulation, and other adaptive processes in many groups of animals. In Drosophila, pigmentation can differ dramatically among closely related taxa, presenting a good opportunity to dissect the genetic changes underlying species divergence. In this report, we investigate the genetic basis of color pattern variation between two allopatric subspecies of Drosophila malerkotliana, a widespread member of the ananassae species subgroup. In D. malerkotliana malerkotliana, the last three abdominal segments are darkly pigmented in males but not in females, while in D. malerkotliana pallens both sexes lack dark pigmentation. Composite interval mapping in F(2) hybrid progeny shows that this difference is largely controlled by three quantitative trait loci (QTL) located on the 2L chromosome arm, which is homologous to the 3R of D. melanogaster (Muller element E). Using highly recombinant introgression strains produced by repeated backcrossing and phenotypic selection, we show that these QTL do not correspond to any of the candidate genes known to be involved in pigment patterning and synthesis in Drosophila. These results, in combination with similar analyses in other Drosophila species, indicate that different genetic and molecular changes are responsible for the evolution of similar phenotypic traits in different lineages. This feature makes Drosophila color patterns a powerful model for investigating how the genetic basis of trait evolution is influenced by the intrinsic organization of regulatory pathways controlling the development of these traits.