Biological Affinities Between Migrant and Parental Populations in Punjab, India

In the present study, we have examined biological affinities between parental population, migrants from Pakistan after 1947 and non-Punjabi migrants from other states of India in Punjab. About 500 adult individuals of both sexes from 300 families among three groups were measured for 16 anthropometric and physiometric variables. Analysis of both univariate and multivariate suggests an overall significant migration effect in almost all variables especially anthropometric measurements between both sexes. The higher discrimination has been found in migrants from other states of India with reference to anthropometric traits as compared to other two populations. This is because of more genetic heterogeneity as would be expected from many states and many ethnicities of migrants. It was also found that the other two populations are more or less qualitatively similar, which reflects common ethnohistorical or geographic affiliations. However, overall, women showed a greater migration effect than men.     

Qualitative dermatoglyphic affinities between the migrant groups of fishermen of Puri Coast, India

Finger and palm prints of 677 subjects (395 males and 282 females) were analyzed for 11 qualitative dermatoglyphic variables to study the relationship between the three migrant groups of fishermen of Puri. Sanghvi's X2-distance gives configuration confirmatory to caste affiliations, quite clearly in males, but to a lesser degree in females. A comparison with distance configurations obtained for quantitative finger/palm variables and for anthropometric/genetic markers suggests that the qualitative dermatoglyphic traits stand out as useful markers in more convincingly portraying the affinities at the level of sub-castes.     

Biological affinities between the migrant groups of fishermen of Puri Coast, Orissa, India

Biological affinities between the three endogamous groups of marine fishermen of Puri are examined with the help of nine anthropometric measurements and 22 dermatoglyphic traits of fingers and palms. The results are interpreted in the light of their ethnic, geographical, and migrational backgrounds. Multiple discriminant analysis and Mahalanobis's generalized distances suggest higher discrimination of populations with reference to anthropometric traits as compared to that in dermatoglyphic variables. While the nature of interpopulation distances conforms to the geographic pattern in anthropometrics, no clear picture emerges in the dermatoglyphic distances supporting either ethnic or geographic evidence.     

Effects of Migration on Genetic Variability and Parent–Offspring Correlation Coefficients in Anthropometric and Physiometric Phenotypes Among Three Groups of Population in Punjab, India

In the present study, we examined the migration effects on genetic variabilities and heritabilities patterns between three groups of population like parental population in Punjab, migrant from Pakistan, and migrant from other states of India in Punjab using anthropometric and physiometric traits. A total of 500 adult individuals from 300 families were studied. Statistical comparisons were carried out through mean coefficients, Student’s t test, heritability, and regression analysis. The results suggest a significant migration effect on almost all traits. Correlation coefficient for first-degree relatives, the slope factors, and heritabilities for almost all variables have been found significant among the three groups of populations. However, the discrimination is more prominent among migrant from other states of India because of more genetic heterogeneity.     

Quantitative palmar dermatoglyphics and the assessment of population affinities: data from marine fishermen of Puri, India

Variation in quantitative dermatoglyphics among three endogamous groups of marine fishermen of Puri Coast, India, is greater for the palmar variables than for the fingers. This is the case in both the sexes. The pattern of population affinities, however, differs for the males and females. In order to evaluate the importance of palmar variables in population studies, the results in males are compared with those of finger variables and anthropometrics. There is no significant heterogeneity between the groups for finger variables. Although significant intergroup variability is observed in the palmar and anthropometric traits, the two sets of results are not in the same direction. Palmar dermatoglyphic relationships reflect the caste affiliations, while the anthropometric are in line with geographic proximity.     

Clan-structured migration and phenotypic differentiation in the Jirels of Nepal

This paper examines the impact of clan-structured migration on the between-village differentiation of the Jirels, a tribal population of eastern Nepal. The Jirel population is geographically restricted to nine villages, all of which were sampled to some extent for this study. Data on five head measurements, stature, and digital ridge counts are utilized to illustrate the patterns of phenotypic variation. Multivariate statistical techniques are used to assess the extent to which clan membership and associated patterns of marital exchange influence the population structure of the Jirels. The phenotypic characteristics of randomly generated migrant sets are compared to those of the observed clan-structured sets, demonstrating the clan-related phenotypic nonrandomness of migrants. The results indicate that clan-structured migration may significantly influence the amount of between-village variation. Clan structure may be a significant factor in determining patterns of variation and should not be ignored in studies of microdifferentiation in tribal populations.     

Landscape genetics and hierarchical genetic structure in Atlantic salmon: the interaction of gene flow and local adaptation

Disentangling evolutionary forces that may interact to determine the patterns of genetic differentiation within and among wild populations is a major challenge in evolutionary biology. The objective of this study was to assess the genetic structure and the potential influence of several ecological variables on the extent of genetic differentiation at multiple spatial scales in a widely distributed species, the Atlantic salmon, Salmo salar . A total of 2775 anadromous fish were sampled from 51 rivers along the North American Atlantic coast and were genotyped using 13 microsatellites. A Bayesian analysis clustered these populations into seven genetically and geographically distinct groups, characterized by different environmental and ecological factors, mainly temperature. These groups were also characterized by different extent of genetic differentiation among populations. Dispersal was relatively high and of the same magnitude within compared to among regional groups, which contrasted with the maintenance of a regional genetic structure. However, genetic differentiation was lower among populations exchanging similar rates of local as opposed to inter-regional migrants, over the same geographical scale. This raised the hypothesis that gene flow could be constrained by local adaptation at the regional scale. Both coastal distance and temperature regime were found to influence the observed genetic structure according to landscape genetic analyses. The influence of other factors such as latitude, river length and altitude, migration tactic, and stocking was not significant at any spatial scale. Overall, these results suggested that the interaction between gene flow and thermal regime adaptation mainly explained the hierarchical genetic structure observed among Atlantic salmon populations.     

A genetic study of syndactyly in Utah

Abstract

Pregnancy histories of 470 ever‐married women aged 40 years and older from three endogamous groups of marine fishermen of Puri, Orissa, are analyzed to estimate Crow's index of opportunity for selection. All these populations are migrants. The value of I ranges from 0.63 to 1.08. The results are interpreted in the light of their ethno‐historical, migratory backgrounds, degree of isolation, and population sizes. A comparison with published Indian data is also made.     

Genetic aspects of migration in a rhesus monkey population

Gene frequency distributions in subdivided populations are affected by migration of individuals between groups. This paper considers the effects of such migration on blood protein allele frequency distributions in social groups of the Cayo Santiago rhesus macaque colony. Gene frequencies for complete social groups and their migrant and natal segments were analyzed at four points within a four year period in the colony's history. Gene frequencies varied between the migrant segments of different groups. Gene frequencies of migrant segments of particular groups also varied substantially with time. Usually, but not always, the presence of migrants in groups reduced the levels of inter-group gene frequency differentiation. We suggest that our findings are explained by a model in which the recruitment of immigrants into social groups is largely random with respect to individual genotypes. Such a model implies that migration contributes to both stochastic and directed changes in gene frequencies in rhesus and similarly substructured populations.     

Genetic structure of an isolated native population group of northern Sibiria, the Nganasani (Tavgi) of the Taimyr. II. An analysis of intrapopulation variability

Chi-square contingency table analysis of phenotypic (genotypic) and gene frequencies of erythrocyte and blood serum groups and enzymes in a group of reindeer hunter and fishermen revealed heterogeneity within the population studied. Four out of twelve loci which have been compared were found to be involved in the process of differentiation into two local subgroups (subpopulations). No statistical differences have been observed between samples arbitrarily representing three generations. The data obtained support the hypothesis that the whole population still preserves the state of the stability. Traditional migration from adjacent populations close to nganasans by language and culture has made an important contribution into heterogeneity found in nganasans.     

Phenotypic consequences of nonrandom migration in the Jirels of Nepal

The phenotypic structure of human populations is shaped by a number of factors such as population size and marital migration. This paper examines the impact of migration on the between-village phenotypic differentiation of the Jirels, a tribal group of eastern Nepal. Data on stature and five cranial measurements for 526 individuals (males and females) are utilized to illustrate the patterns of phenotypic variation. A permutation method is used to generate the phenotypic consequences of random migration constrained to observed levels of movement. The results suggest that Jirel migration is nonrandom and that it produces higher levels of phenotypic differentiation than would result from a random migration process.     

Are temporary migrants escapees of the one-child-per-family population policy: a revisit to the detachment hypothesis

Using Hubei province as a case study, this paper retests the detachment hypothesis against the three conventional hypotheses regarding migration-fertility linkage (i.e., selectivity, disruption, and adaptation hypotheses) in explaining migrant and non-migrant fertility differentials in China. The analysis of yearly order-specific birth probabilities suggests that temporary migrants exhibit a significantly higher probability of having a second or higher order birth than comparable permanent migrants and non-migrants. This higher fertility among temporary migrants occurs after migration; temporary migrants actually do not differ from non-migrants in fertility before migration. But permanent migrants experience no significant change in their fertility after migration. The results lend a strong support to the detachment hypothesis, which best explains the fertility differentials between migrant and non-migrant populations in contemporary China; the separation of temporary migrants' actual residence from their official one does lead to a greater likelihood among temporary migrants to have unplanned births.     

R-matrix analysis and patterns of gene flow in India

An appraisal on the usefulness of R-matrix analysis and the model of Harpending and Ward (1982) to study the population structure of Indian populations is made in the light of prevalent marriage patterns, caste structure, and cultural specificity of the region. With the help of available data on the migration histories and geographical backgrounds of marine fishermen on the east coast of India, and through the historical analysis of marriage patterns, it is demonstrated that the routine inferences based on the regression plots of average heterozygosity versus genetic distance from the centroid may not generally be apt for the Indian situation. Increased heterozygosity among migrant fishermen seems to have resulted from mating patterns within this community rather than from external gene flow. In either case, the genetic implications are supposedly identical. Nevertheless, when making inferences regarding local population structure it is important to have detailed knowledge of mating patterns and the cultural context of the region under study.     

Alternative developmental pathways and the propensity to migrate: a case study in the Atlantic salmon

Migratory behaviour with its associated phenotypic changes is generally viewed as an adaptive strategy because it incurs survival or reproductive advantages to migrants. The development of a migrant phenotype is believed to be controlled by threshold mechanisms, where individuals emigrate only after surpassing a particular body size but delay migration if below. For such a strategy to respond to natural selection, part of the phenotypic variance in the propensity to migrate must be explained by variation in additive genetic effects. Here, we use data gathered in the field and from a common rearing experiment to test for a genetic basis associated with seaward migration in Atlantic salmon (Salmo salar L.). We document a high heritability of the liability trait underlying the propensity to emigrate in juvenile salmon, and significant differences between offspring grouped according to their sires in body-size threshold values above which emigration takes place. The presence of additive genetic variance in both the liability and thresholds makes the onset of migration a process sensitive to selection and may therefore constitute an important explanatory mechanism for the interpopulation differences in the size at seaward migration observed in this species.     

Environment, migratory tendency, phylogeny and basal metabolic rate in birds

Basal metabolic rate (BMR) represents the minimum maintenance energy requirement of an endotherm and has far-reaching consequences for interactions between animals and their environments. Avian BMR exhibits considerable variation that is independent of body mass. Some long-distance migrants have been found to exhibit particularly high BMR, traditionally interpreted as being related to the energetic demands of long-distance migration. Here we use a global dataset to evaluate differences in BMR between migrants and non-migrants, and to examine the effects of environmental variables. The BMR of migrant species is significantly higher than that of non-migrants. Intriguingly, while the elevated BMR of migrants on their breeding grounds may reflect the metabolic machinery required for long-distance movements, an alternative (and statistically stronger) explanation is their occupation of predominantly cold high-latitude breeding areas. Among several environmental predictors, average annual temperature has the strongest effect on BMR, with a 50% reduction associated with a 20 degrees C gradient. The negative effects of temperature variables on BMR hold separately for migrants and non-migrants and are not due their different climatic associations. BMR in migrants shows a much lower degree of phylogenetic inertia. Our findings indicate that migratory tendency need not necessarily be invoked to explain the higher BMR of migrants. A weaker phylogenetic signal observed in migrants supports the notion of strong phenotypic flexibility in this group which facilitates migration-related BMR adjustments that occur above and beyond environmental conditions. In contrast to the findings of previous analyses of mammalian BMR, primary productivity, aridity or precipitation variability do not appear to be important environmental correlates of avian BMR. The strong effects of temperature-related variables and varying phylogenetic effects reiterate the importance of addressing both broad-scale and individual-scale variation for understanding the determinants of BMR.     

Anthropological studies in Assam, India. 6. Differentiation processes among Assamese populations

In 1978-79 13 Assamese populations--two Muslim groups, five Mongoloid groups and 6 Hindu caste groups--have been investigated for the distribution of anthropometric, anthroposcopic and dermatoglyphic traits as well as for the distribution of ABO blood groups and PTC taste sensitivity. Except for finger ridge patterns all traits under investigation showed a marked intergroup variability. For anthropometric, anthroposcopic and dermatoglyphic traits a clear differentiation in Mongoloid populations on one hand and Hindu caste groups on the other could be observed and be substantiated by results of corresponding distance analyses. With regard to Muslims it has to be distinguished between Marias who seem to be more closely related to Mongoloid populations and Sheikhs whose phenotypic appearance is more like that of the Hindu caste groups. The results are discussed.     

Environmental gradients shape the genetic structure of two medicinal Salvia species in Jordan

• Environmental gradients, and particularly climatic variables, exert a strong influence on plant distribution and, potentially, population genetic diversity and differentiation. Differences in water availability can cause among‐population variation in ecological processes and can thus interrupt populations’ connectivity and isolate them environmentally. The present study examines the effect of environmental heterogeneity on plant populations due to environmental isolation unrelated to geographic distance.
• Using AFLP markers, we analyzed genetic diversity and differentiation among 12 Salvia spinosa populations and 13 Salvia syriaca populations from three phytogeographical regions (Mediterranean, Irano‐Turanian and Saharo‐Arabian) representing the extent of the species’ geographic range in Jordan. Differences in geographic location and climate were considered in the analyses.
• For both species, flowering phenology varied among populations and regions. Irano‐Turanian and Saharo‐Arabian populations had higher genetic diversity than Mediterranean populations, and genetic diversity increased significantly with increasing temperature. Genetic diversity in Salvia syriaca was affected by population size, while genetic diversity responded to drought in S. spinosa. For both species, high levels of genetic differentiation were found as well as two well‐supported phytogeographical groups of populations, with Mediterranean populations clustering in one group and the Irano‐Turanian and Saharo‐Arabian populations in another. Genetic distance was significantly correlated to environmental distance, but not to geographic distance.
• Our data indicate that populations from moist vs. arid environments are environmentally isolated, where environmental gradients affect their flowering phenology, limit gene flow and shape their genetic structure. We conclude that environmental heterogeneity may act as driver for the observed variation in genetic diversity.

     

Do Migrants Degrade Coastal Environments? Migration,Natural Resource Extraction and Poverty in North Sulawesi,Indonesia

Recent literature on migration and the environment has identified key mediating variables such as how migrants extract resources from the environment for their livelihoods, the rate and efficiency of extraction, and the social and economic context within which their extraction occurs. This paper investigates these variables in a new ecological setting using data from coastal fishing villages in North Sulawesi, Indonesia. We do not find as many differences between migrant and non-migrant families regarding destructive fishing behavior, technology, and investment as might have been expected from earlier theories. Instead, the context and timing of migrant assimilation seems to be more important in explaining apparent associations of migration and environmental impacts than simply migrants themselves. This finding fits well with recent literature in the field of international migration and immigrant incorporation.     

Perceived wintering latitude determines timing of song output in a migratory bird

Migratory bird populations frequently consist of individuals that overwinter variable distances from the breeding site. Seasonal changes in photoperiod, which varies with latitude, underlie seasonal changes in singing frequency in birds. Therefore, migratory populations that consist of individuals that overwinter at different latitudes with large overwintering ranges could experience within‐population variation in seasonal production of song. To test the influence of overwintering latitude on intrapopulation variance in song production in the spring, we subjected two groups of Eastern Song Sparrows (Melospiza melodia melodia) from the same partially migratory breeding population to different photoperiodic schedules associated with a 1,300‐km difference in overwintering location. One group remained on the natural photoperiodic schedule of the breeding site (resident group) while the other group experienced a nonbreeding photoperiod that mimicked a southern migration in the fall followed by a northern migration back to the breeding site in the spring (migratory group). We compared song output between the two groups in three different stages (nonbreeding, prebreeding, and breeding). Little singing occurred during nonbreeding stage sample dates (20 November, 6 December) for the resident group, and no singing occurred for the migrant group. During the prebreeding stage (27 January, 7 February), significantly more singing occurred in the resident group than in the migrant group. During the breeding stage (21 March, 4 April), after a simulated migration for the migrants, song output was similar in both groups. These results suggest that within‐population variation in wintering latitude may contribute to variation in seasonal changes in singing behavior, which may covary with readiness to breed. Studies utilizing confirmed migrants and residents, rather than merely simulated migrants and residents, are also needed to better understand these processes.     

Reverse migration as a cause of vagrancy

Capsule Reverse migration in autumn does not occur to the same degree in all species of migrants, but is related to migratory direction.

Aims To identify factors determining degree of reverse migration and specifically to test whether it occurs in long-distance migrant species irrespective of their standard (normal) migration direction. Methods Multiple regression analysis on the number of individuals occurring as reverse migrants observed in northwest European countries.

Methods Multiple regression analysis on the number of individuals occurring as reverse migrants observed in northwest European countries.

Results The number of reverse migrants observed in northwest European countries is strongly correlated with standard migratory direction, estimated population size and detectability, but an effect of the distance travelled from the breeding areas is not supported. The pattern holds true for subsamples of the data set, including British and Irish records or Scandinavian records only, and when controlling for phylogeny.

Conclusion Birds that migrate eastward in autumn from their breeding grounds, mostly in eastern Europe, are more likely to consistently reverse migrate than those species migrating southward mostly from southern Europe.