University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

We conducted a survey to analyze the genetic epidemiology of trisomy 21 Down syndrome births in the Sundarban delta region of India. In this region, inhabitants are chiefly from marginalized poor tribal communities and have lived in extremely low socioeconomic condition for several generations. Microsatellite genotyping revealed an meiosis I/meiosis II ratio that is different from the previous reports on the Down syndrome populations from other parts of the world. Analyses of distribution of achiasmate nondisjunction at maternal meiosis I in interaction with different maternal age groups (young, middle, and old) revealed a very concordant pattern to that of urban and semi-urban Down syndrome cases previously studied by our group. However, the frequency of achiasmate meiosis is much lower, which suggests that extreme low socioeconomic exposure imparts risk of chromosomal nondisjunction even when the maternal chromosomes 21 engage in proper chiasma formation at prophase I of oogenesis. © 2013 Springer-Verlag.

Zoology

GENERAL

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Journal of Community Genetics

Altered incidence of meiotic errors and Down syndrome birth under extreme low socioeconomic exposure in the Sundarban area of India

Citizenship is essentially about membership in society which enables citizens to participate in the affairs of their community on roughly equal terms and culturally enjoins upon them to collectively surmount their commonly felt problems, such as poverty. The role of Self-Help Groups (SHGs) should be understood in this context. Through observation and conversation-analysis methods, this paper studies two SHGs in India: the successful one practiced citizenship, envisaged a sense of community and made progress towards capacity building and empowerment, especially pertaining to education, health and sanitation. It concludes that in developing countries, citizens acquire the appropriate virtues through participation in the programmes linked with their vision of well-being and thus strengthen the cause of citizenship.

Journal of Asian and African Studies

Citizenship in Practice: Poverty Reduction and Self-Help Groups

World University root node

Missegregation of Chromosome 21 In Oocyte: What Genetic Causes Imperil a Healthy Egg to Have Bad Fate?

Down Syndr

Risk factors for Down Syndrome birth: Understanding the causes from genetics and epidemiology

To explore the role of CRELD1 variants on congenital heart defects, we sequenced the entire reading frame of CRELD1 in the samples from Kolkata and adjoining areas. Nearly, 400 participants were included in the genetic association study and they were stratified as Down syndrome (DS) with atrioventricular septal defect (AVSD), DS without AVSD, euploid with AVSD, and euploid without AVSD. A significant association was found between AVSD and three polymorphisms, namely rs9878047 (c.1049-129T>C), rs3774207 (c.1119C>T), and rs73118372 (c.1136T>C) among the Down syndrome and euploid individuals. The polymorphism rs73118372, involves a transition (c.1136T>C) that leads to change in amino acid methionine to threonine which alters protein secondary structure as confirmed by the bioinformatics software SOPMA. In addition, two haplotypes, C-T-C and C-T-T, in the order of loci rs9878047-rs3774207-rs73118372 were associated with incidence of AVSD among euploid and Down syndrome, with a slightly higher odds ratio in the later group. We hypothesize that these haplotypes increase the risk of AVSD, and the susceptibility is exacerbated in DS, possibly due to the trisomy 21 genetic background. Moreover, we report for the first time on an interaction between the mutant alleles of rs3774207 and rs73118372 which could disrupt the delicate balance between different CRELD1 isoforms. © 2012 Wiley Periodicals, Inc.

American Journal of Medical Genetics, Part A

Polymorphic haplotypes of CRELD1 differentially predispose Down syndrome and euploids individuals to atrioventricular septal defect

Down Syndrome (DS) is the most commonly identified genetic form of intellectual disability and is characterized by specific phenotypic disposition with set of congenital defects. Epidemiologic study of DS was initiated immediately after its discovery in mid 1800s and with the advent of karyotyping its etiology was identified. It is the triplication of human chromosome 21 (Ch21), that is the presence of an extra copy of Ch21, causes the typical phenotypic features of DS. The supernumerary Ch21 arises due to NDJ (NDJ) of the chromosome at anaphase of meiosis during parental gametogenesis. It is now estimated that nearly 95% of all live born DS have an extra copy of Ch21 due to meiotic NDJ, whereas other forms of DS namely, somatic mosaicism due to mitotic error in embryonic development and translocation of Ch21 account for the rest. For overwhelming majority of cases within the non disjoined category, 90% of the error arises in oocyte. It is probably the protracted phase of oogenesis that makes the women more susceptible to NDJ than their male partners. Detail epidemiologic and population based research have identified advanced maternal age and altered pattern of meiotic recombination as two risk factors that make the oocyte susceptible to acquire faulty number of chromosome. The birth prevalence study revealed a progressive increase in incidence of DS birth with advancing age of women and several hypotheses have been put forward to explain the maternal age effect on meiotic chromosome segregation system. STR (short tandem repeat) markers based genotyping of DS family demonstrated that ̃80% of maternal errors occur in first phase of meiosis, that is meiosis I (MI), and there is fall in usual recombination frequency on Ch21 that experience NDJ at MI. With chromosome mapping approach, workers have succeeded in identifying the erroneous placement of chiasmata on long arm of Ch21 that predispose the chromosome to mis-segregation. Refined analyses with large sample size have identified a potential interaction between maternal age and altered pattern of recombination.Beside maternal age and altered recombination, several habitual or environmental factors have been identified to associate with DS birth. This include, maternal habit of smoking, chewing tobacco and contraceptive pill, alcohol and coffee consumption, maternal exposure to radiation, low socio-economic livelihood etc. It seems almost certain that environmental risk factors for chromosome NDJ do exist, but not yet confirmed. With incisive approach to identify the relation among recombination, maternal age and environmental risk factors, workers have elucidated a complicated interaction among these three factors. Moreover, polymorphism of certain genes in folic acid metabolism pathway has been identified as predisposing to DS conception among the women. All these discoveries unequivocally suggest that the etiology of DS birth is complicated and multidimensional. In this review we will focus on the present understanding of the maternal risk factors of DS birth with brief description on recent developments in the field of Down syndrome research. Additionally, we will also discuss the future scope of research and their possible implication in designing the preventive measures.

New Developments in Down Syndrome Research

Down syndrome birth: Impact of environmental risk factors on maternal meiotic errors

Down syndrome birth is attributable to multiple maternal risk factors that include both genetic and environmental challenges, but there is limited understanding of the complicated interactions among these factors. In the present study, a case-control analysis of approximately 400 infants with or without suspected Down syndrome reported between 2003 and 2009 and their parents in and around Kolkata, India, was conducted. Maternal exposure to 2 environmental risk factors (smokeless chewing tobacco and oral contraceptive pills) was recorded, and families were genotyped with microsatellite markers to establish the origin of nondisjunction errors as well as recombination patterns of nondisjoined chromosome 21. With logistic regression models, the possible interactions among all of these risk factors, as well as with maternal age, were explored. Smokeless chewing tobacco was associated with significant risk for meiosis II nondisjunction and achiasmate (nonexchange) meiosis I error among young mothers. By contrast, the risk due to oral contraceptive pills was associated with older mothers. Study results suggest that the chewing tobacco risk factor operates independently of the maternal age effect, whereas contraceptive pill-related risk may interact with or exacerbate age-related risk. Moreover, both risk factors, when present together, exhibited a strong age-dependent effect. © 2011 The Author.

American Journal of Epidemiology

Epidemiology of down syndrome: New insight into the multidimensional interactions among genetic and environmental risk factors in the oocyte

Etiology of Down syndrome: Risk of advanced maternal age and altered meiotic recombination for chromosome 21 nondisjunction:

We analysed the family linkage data obtained from short tandem repeat (STR) genotyping of 212 unrelated Indian families having a single Down syndrome (DS) baby each, in order to explore the incidence and aetiology of this human aneuploidy in our cohort. The estimated values of maternal meiotic I and meiotic II non-disjunction (NDJ) errors of chromosome 21 (Ch 21) were ~78 and ~22%, respectively. Within the paternal outcome group, about 47 and 53% were accounted for NDJ at meiosis I and meiosis II, respectively. We estimated only ~2% post-zygotic mitotic errors. The comparison of average age of conception between controls and DS-bearing mothers revealed a significant difference (P<0001) with DS-bearing women were on an average older than controls and meiotic II non-disjoined mothers were oldest among meiotic outcome groups. Our linkage analysis suggested an overall reduction in recombination by more than 50% on meiotic I non-disjoined maternal Ch 21 with error prone to susceptible chiasma formation within the ~51 kbp segment near the telomeric end. We stratified meiotic I non-disjoined women in three age groups, viz. young (28 years), middle (29-34 years) and old (35 years) and found linear decrease in the frequency of achiasmate meiosis from the young to the old group. In contrary, a linear increase in the multiple chiasma frequency from the young to the old group was observed. Considering these results together, we propose that the risk factors for Ch 21 NDJ are of two types, one being maternal age-independent and the other being maternal age-dependent. Moreover, a comparison of our present Indian dataset with that of other published data of ethnically different populations suggested that the genetics that underlies the NDJ of Ch 21 is probably universal irrespective of racial difference across human populations. The present study is the first population-based report on any DS cohort from the Indian subcontinent and our work will help future workers in understanding better the aetiology of this birth defect. © 2010 Cambridge University Press.

Genetics Research

Chromosome 21 non-disjunction and Down syndrome birth in an Indian cohort: Analysis of incidence and aetiology from family linkage data

Advanced maternal age is a well-documented risk factor of chromosome 21 nondisjunction in humans, but understanding of this association at the genetic level is still limited. In particular, the state of maternal genetic age is unclear. In the present study, we estimated maternal genetic age by measuring telomere length of peripheral blood lymphocytes among age-matched mothers of children with Down syndrome (cases: N = 75) and mothers of euploid children (controls: N = 75) in an age range of 18-42 years. All blood samples were taken within 1 week of the birth of the child in both cases and controls. The telomere length estimation was performed by restriction digestion-Southern blot hybridization method. We stratified the cases on the basis of centromeric STR genotyping into maternal meiosis I (N = 48) and maternal meiosis II (N = 27) nondisjunction groups and used linear regression to compare telomere length as a function of age in the euploid, meiosis I and meiosis II groups. Our results show that all three groups have similar telomere length on average for younger mothers. As age increases, all groups show telomere loss, but that loss is largest in the meiosis II mother group and smallest in the euploid mother group with the meiosis I mother group in the middle. The regression lines for all three were statistically significantly different from each other (p < 0.001). Our results do not support the theory that younger women who have babies with Down syndrome do so because are 'genetically older' than their chronological age, but we provide the first evidence that older mothers who have babies with Down syndrome are "genetically older" than controls, who have euploid babies at the same age. We also show for the first time that telomere length attrition may be associated in some way with meiosis I and meiosis II nondisjunction of chromosome 21 and subsequent Down syndrome births at advanced maternal age. © 2010 Springer-Verlag.

Human Genetics

Telomere length is associated with types of chromosome 21 nondisjunction: A new insight into the maternal age effect on Down syndrome birth

Down syndrome caused by meiotic nondisjunction of chromosome 21 in humans, is well knownto be associated with advanced maternal age, but success in identifying and understanding other risk factors has been limited. Recently published work in a U.S. population suggested intriguing interactions between the maternal age effect and altered recombination patterns during meiosis, but some of the results were counter-intuitive. We have tested these hypotheses in a population sample from India, and found that essentially all of the results of the U.S. study are replicated even in our ethnically very different population. We examined meiotic recombination patterns in a total of 138 families from the eastern part of India, each with a single free trisomy 21 child.Wegenotyped each family with a set of STR markers using PCR and characterized the stage of origin of nondisjunction and the recombination pattern of maternal chromosome 21 during oogenesis. Our sample contains 107 maternal meiosis I errors and 31 maternal meiosis II errors and we subsequently stratified them with respect to maternal age and the number of detectable crossover events. We observed an association between meiosis I nondisjuncion and recombination in the telomeric 5.1Mb of chromosome 21. By contrast, in meiosis II cases we observed preferential pericentromeric exchanges covering the proximal 5.7Mb region, with interaction between maternal age and the location of the crossover. Overall reduction of recombination irrespective of maternal age is also evident in meiosis I cases. Our findings are very consistent with previously reported data in a U.S. population and our results are the first independent confirmation of those previous reports. This not only provides much needed confirmation of previous results, but it suggests that the genetic etiology underlying the occurrence of trisomy 21 may be similar across human populations. © 2009 Wiley-Liss, Inc.

Etiology of down syndrome: Evidence for consistent association among altered meiotic recombination, nondisjunction, and maternal age across populations

Institutions are essentially broadly agreed norms, rules and routines. They might have arisen out of social conflicts with strong influence of power relations, but they also face the demands of democracy. While studying NGOs as political institutions, particularly in the context of a number of developing countries, this article argues that the political context of their action is determined by their relationship with the donors and social movements. Second, NGOs promote democracy when they redefine participation in terms of their relationship with state and society; and contribute to improve the quality of participation, although with much less success in promoting internal democracy. © 2009 SAGE Publications.