Showing papers by "Ranjan Deka published in 2020"

Evolutionary history of modern Samoans

Abstract: Archaeological studies estimate the initial settlement of Samoa at 2,750 to 2,880 y ago and identify only limited settlement and human modification to the landscape until about 1,000 to 1,500 y ago. At this point, a complex history of migration is thought to have begun with the arrival of people sharing ancestry with Near Oceanic groups (i.e., Austronesian-speaking and Papuan-speaking groups), and was then followed by the arrival of non-Oceanic groups during European colonialism. However, the specifics of this peopling are not entirely clear from the archaeological and anthropological records, and is therefore a focus of continued debate. To shed additional light on the Samoan population history that this peopling reflects, we employ a population genetic approach to analyze 1,197 Samoan high-coverage whole genomes. We identify population splits between the major Samoan islands and detect asymmetrical gene flow to the capital city. We also find an extreme bottleneck until about 1,000 y ago, which is followed by distinct expansions across the islands and subsequent bottlenecks consistent with European colonization. These results provide for an increased understanding of Samoan population history and the dynamics that inform it, and also demonstrate how rapid demographic processes can shape modern genomes.

A missense variant in CREBRF is associated with taller stature in Samoans.

Abstract: Objectives Studies have demonstrated that rs373863828, a missense variant in CREBRF, is associated with a number of anthropometric traits including body mass index (BMI), obesity, percent body fat, hip circumference, and abdominal circumference. Given the biological relationship between height and adiposity, we hypothesized that the effect of this variant on BMI might be due in part to an association of this variant with height. Methods We tested the hypothesis that minor allele of rs373863828 is associated with height in a Samoan population in two adult cohorts and in a separate cohort of children (age 5-18 years old) using linear mixed modeling. Results We found evidence of a strong relationship between rs373863828 and greater mean height in Samoan adults (0.77 cm greater average height for each copy of the minor allele) with the same direction of effect in Samoan children. Conclusions These results suggest that the missense variant rs373863828 in CREBRF, first identified through an association with larger BMI, may be related to an underlying biological mechanism affecting overall body size including stature.

Exploring the Paradoxical Relationship of a Creb 3 Regulatory Factor Missense Variant With Body Mass Index and Diabetes Among Samoans: Protocol for the Soifua Manuia (Good Health) Observational Cohort Study.

Abstract: Background: The prevalence of obesity and diabetes in Samoa, like many other Pacific Island nations, has reached epidemic proportions. Although the etiology of these conditions can be largely attributed to the rapidly changing economic and nutritional environment, a recently identified genetic variant, rs373863828 (CREB 3 regulatory factor, CREBRF: c.1370G>A p.[R457Q]) is associated with increased odds of obesity, but paradoxically, decreased odds of diabetes. Objective: The overarching goal of the Soifua Manuia (Good Health) study was to precisely characterize the association of the CREBRF variant with metabolic (body composition and glucose homeostasis) and behavioral traits (dietary intake, physical activity, sleep, and weight control behaviors) that influence energy homeostasis in 500 adults. Methods: A cohort of adult Samoans who participated in a genome-wide association study of adiposity in Samoa in 2010 was followed up, based on the presence or absence of the CREBRF variant, between August 2017 and March 2019. Over a period of 7-10 days, each participant completed the main study protocol, which consisted of anthropometric measurements (weight, height, circumferences, and skinfolds), body composition assessment (bioelectrical impedance and dual-energy x-ray absorptiometry), point-of-care glycated hemoglobin measurement, a fasting blood draw and oral glucose tolerance test, urine collection, blood pressure measurement, hand grip strength measurement, objective physical activity and sleep apnea monitoring, and questionnaire measures (eg, health interview, cigarette and alcohol use, food frequency questionnaire, socioeconomic position, stress, social support, food and water insecurity, sleep, body image, and dietary preferences). In January 2019, a subsample of the study participants (n=118) completed a buttock fat biopsy procedure to collect subcutaneous adipose tissue samples. Results: Enrollment of 519 participants was completed in March 2019. Data analyses are ongoing, with results expected in 2020 and 2021. Conclusions: While the genetic variant rs373863828, in CREBRF, has the largest known effect size of any identified common obesity gene, very little is currently understood about the mechanisms by which it confers increased odds of obesity but paradoxically lowered odds of type 2 diabetes. The results of this study will provide insights into how the gene functions on a whole-body level, which could provide novel targets to prevent or treat obesity, diabetes, and associated metabolic disorders. This study represents the human arm of a comprehensive and integrated approach involving humans as well as preclinical models that will provide novel insights into metabolic disease.

Prolactin gene polymorphism in crossbred cattle of Assam and its association with productive and reproductive traits

Abstract: The present investigation was designed to study the performance of crossbred cows as well as to identify polymorphism in genomic sequences of PRL gene and its association with various reproductive and productive traits of crossbred cows maintained at the Bull Mother Farm, Barapeta, Assam. A total of 40 cows were utilized to study the polymorphism of the PRL gene, the results of which showed polymorphic banding pattern in most of the samples of crossbred cows with respect to the gene under study. Polymerase Chain Reaction-Restriction Fragment Length Polymorphism studies on PRL gene in crossbred cows, using Rsa I restriction enzyme revealed three types of fragment pattern, arbitrarily designated as AA (156 bp), AB (74, 82 and 156 bp), BB (74 and 82 bp) genotype. The frequencies of A and B alleles were calculated as 0.534 and 0.466 and those of AA, AB and BB genotypes as 0.334, 0.400 and 0.266 respectively. The prolactin genotypes were found to be significantly related to age at sexual maturity, age at first calving, first lactation milk yield. The crossbred cattle with AB genotype showed better performance than those with AA and BB genotype in the population studied.

Management of Cervico-Vaginal Prolapse in a Pre-partum Crossbred Cow: A Case Report

Abstract: Large ruminants suffering from Cervicovaginal prolapse is often comes across by veterinarians. Ruminants like Cattle and Buffalo may suffer from cervico vaginal prolapsed. Extensive elaboration of incidence and symptoms in cows has been documented (Roberts, 1971 and Arthur et al., 1989). Suturing the vulvar lips using various suture patterns although present initial eversion of vagina into the vestibule is difficult to achieve. The present study was carried out to evaluate the clinical management of Cervico-vaginal prolapse in a pregnant cow by application of retention sutures.