Articles written in Journal of Biosciences
Volume 19 Issue 5 December 1994 pp 513-528
At zygotene/pachytene stage of meiosis in mammalian testis, the X—Y heterobivalent is sequesterd into a heterochromatinized body whose genetic inactivity is shown by lack of uridine incorporation. For the genic level evaluation of the X-inactivation, activities of three X-linked genes were assayed in testicular cell types in the laboratory mouse. While hypoxanthine phosphoribosyl transferase is functional at least up to pachytene stage of primary spermatocytes, glucose-6-phosphate dehydrogenase appears to be active only in the Sertoli cells. No transcript of the muscle specific muscular dystrophin gene was obtained from its regular 5′ promoter. Thus, inactivation of X-linked genes in testis occurs at different stages during spermatogenesis, independently of heterochrornatinizati on of the XY-body. We propose that Xist transcript, the putative regulator of X-inactivation in female soma, is also the regulator in testis. However, due to its extremely low level in testis the transcript may regulate by “spreading” in a gradient and affect the genes in a temporal order. Thus, besides other factors, physical proximity of the genes to Xist may determine the stage of their inactivation.
Volume 38 Issue 1 March 2013 pp 21-26 Brief communications
In India, as in other parts of the world, nonsyndromic cleft lip with or without cleft palate (NSCL±P) is a highly prevalent birth defect, its incidence in males being twice that in females. A case–control association study has been carried out with respect to homocysteine level and
Volume 40 Issue 3 September 2015 pp 539-547 Articles
Incidence of sickle cell trait in India is high in peninsular south, south-eastern, central and south-western India, while in north and north-eastern India, it is absent. Unicentric origin of SCD in the tribals of nilgiri hills in southern India has been proposed. The present study on the frequency of HbS trait and 𝛽-globin gene haplotypes was conducted in the tribal-rich states of Chhattisgarh and Jharkhand to get an insight into the uneven distribution of HbS in India. Jharkhand borders with the HbS-high Odisha and Chhattisgarh, and HbS-low UP, Bihar and Bengal. Cellulose acetate gel electrophoresis was performed on the collected blood samples, to detect sickle haemoglobin (HbS) followed by DNA analysis. HbS associated 𝛽-gene haplotype was constructed for the samples positive for HbS and all the tribals by PCR-RFLP. Out of 805 (Chhattisgarh – 261, Jharkhand – 544; >36% tribals) samples analysed HbS frequency was 13% in Chhattisgarh and 3.3% in Jharkhand. Within Jharkhand, frequencies varied considerably from 10% in Tatanagar to nil in Sahibganj. The Arab-India (AI) haplotype of 𝛽-globin cluster occurred in low frequency, confined mainly to Chhattisgarh. The most abundant haplotype in all the populations was the East Asian, + − − − − − +, rare in HbS, mainly in Sahibganj in east Jharkhand, which lacked AI. Our results indicate that besides the heterozygote advantage againstmalaria, the uneven regional distribution of HbS trait is because of restricted movement of two different populations, Dravidian from the south and Tibeto-Burman from the east into the Indianmainland which failed tomeet, we conjecture, due to severe climatic conditions (deserts and heat) prevailing through parts of central India. Apparently, Jharkhand became a zone of contact between them in recent times.
Volume 45, 2020
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