Search

Spinocerebellar ataxias (SCAs) are a heterogeneous group of neurodegenerative syndromes, characterized by a wide range of muscular weakness and motor deficits, caused due to cerebellar degeneration. The prevalence of the syndromes of SCA varies across the world and is known to be linked to the instability of trinucleotide repeats within the high-end normal alleles, along with susceptible haplotype. We estimated sizes of the CAG or GAA repeat expansions at the SCA1, SCA2, SCA3, SCA12 and frataxin loci among 864 referrals of subjects to genetic counselling and testing (GCAT) clinic, National Institute of Mental Health and Neurosciences, Bengaluru, India, with suspected SCA. The most frequent mutations detected were SCA1 ( $$n=100$$ (11.6%)) and SCA2 ( $$n=98$$ (11.3%)) followed by SCA3 ( $$n=40$$ (4.6%)), FRDA ( $$n=20$$ (2.3%)) and SCA12 ( $$n=8$$ (0.9%)).

Spinocerebellar ataxias (SCAs) are a heterogeneous group of neurodegenerative syndromes, characterized by a wide range of muscular weakness and motor deficits, caused due to cerebellar degeneration. The prevalence of the syndromes of SCA varies across the world and is known to be linked to the instability of trinucleotide repeats within the high-end normal alleles, along with susceptible haplotype. We estimated sizes of the CAG or GAA repeat expansions at the SCA1, SCA2, SCA3, SCA12 and frataxin loci among 864 referrals of subjects to genetic counselling and testing (GCAT) clinic, National Institute of Mental Health and Neurosciences, Bengaluru, India, with suspected SCA. The most frequent mutations detected were SCA1 (n = 100 (11.6%)) and SCA2 (n = 98 (11.3%)) followed by SCA3 (n = 40 (4.6%)), FRDA (n = 20 (2.3%)) and SCA12 (n = 8 (0.9%)).

Culture conditions play an important role in regulating the genomic integrity of Human Pluripotent Stem Cells (HPSCs). We report that HPSCs cultured in Essential 8 (E8) and mTeSR, two widely used media for feeder-free culturing of HPSCs, had many fold higher levels of ROS and higher mitochondrial potential than cells cultured in Knockout Serum Replacement containing media (KSR). HPSCs also exhibited increased levels of 8-hydroxyguanosine, phospho-histone-H2a.X and p53, as well as increased sensitivity to γ-irradiation in these two media. HPSCs in E8 and mTeSR had increased incidence of changes in their DNA sequence, indicating genotoxic stress, in addition to changes in nucleolar morphology and number. Addition of antioxidants to E8 and mTeSR provided only partial rescue. Our results suggest that it is essential to determine cellular ROS levels in addition to currently used criteria i.e. pluripotency markers, differentiation into all three germ layers and normal karyotype through multiple passages, in designing culture media.

SummaryCulture conditions play an important role in regulating the genomic integrity of HPSCs. We report that HPSCs cultured in Essential 8 (E8) and mTeSR, two widely used media for off-feeder culturing of HPSCs, had many fold higher levels of ROS and higher mitochondrial potential than cells cultured in KSR containing media. HPSCs also exhibited increased levels of 8-hydroxyguanosine, phospho-histone-H2A.X and p53, as well as increased sensitivity to γ-irradiation in these two media. HPSCs in E8 and mTeSR had increased incidence of alterations in their DNA sequence, reflecting genotoxic stress, in addition to changes in nucleolar morphology and number. Supplementing E8 and mTeSR with antioxidants provided only a partial rescue. Our results suggest that it is essential to determine cellular ROS levels in designing culture media as it affects the genomic integrity of HPSCs and will limit their use in studying development and in regenerative medicine.HighlightsCulture media can dramatically alter nuclear and nucleolar morphologyHPSCs in E8 and mTeSR media have increased ROS levels and mitochondrial potentialThere is increased nuclei acid damage in HPSCs cultured in E8 and mTeSR mediaNucleolar morphology of HPSCs can act as a “stress reporter”

Y-chromosome Haplogroup O is the dominant lineage of East Asians, comprising more than a quarter of all males on the world; however, its internal phylogeny remains insufficiently investigated. In this study, we determined the phylogenetic position of recently defined markers (L127, KL1, KL2, P164, and PK4) in the background of Haplogroup O. In the revised tree, subgroup O3a-M324 is divided into two main subclades, O3a1-L127 and O3a2-P201, covering about 20 and 35% of Han Chinese people, respectively. The marker P164 is corrected from a downstream site of M7 to upstream of M134 and parallel to M7 and M159. The marker PK4 is also relocated from downstream of M88 to upstream of M95, separating the former O2(*) into two parts. This revision evidently improved the resolving power of Y-chromosome phylogeny in East Asia.

Behar, Doron M. et al.-- The Genographic Consortium, Different lines of evidence point to the resettlement of much of western and central Europe by populations from the Franco-Cantabrian region during the Late Glacial and Postglacial periods. In this context, the study of the genetic diversity of contemporary Basques, a population located at the epicenter of the Franco-Cantabrian region, is particularly useful because they speak a non-Indo-European language that is considered to be a linguistic isolate. In contrast with genome-wide analysis and Y chromosome data, where the problem of poor time estimates remains, a new timescale has been established for the human mtDNA and makes this genome the most informative marker for studying European prehistory. Here, we aim to increase knowledge of the origins of the Basque people and, more generally, of the role of the Franco-Cantabrian refuge in the postglacial repopulation of Europe. We thus characterize the maternal ancestry of 908 Basque and non-Basque individuals from the Basque Country and immediate adjacent regions and, by sequencing 420 complete mtDNA genomes, we focused on haplogroup H. We identified six mtDNA haplogroups, H1j1, H1t1, H2a5a1, H1av1, H3c2a, and H1e1a1, which are autochthonous to the Franco-Cantabrian region and, more specifically, to Basque-speaking populations. We detected signals of the expansion of these haplogroups at ∼4,000 years before present (YBP) and estimated their separation from the pan-European gene pool at ∼8,000 YBP, antedating the Indo-European arrival to the region. Our results clearly support the hypothesis of a partial genetic continuity of contemporary Basques with the preceding Paleolithic/Mesolithic settlers of their homeland., This work was supported by the Institut Pasteur, National Geographic, and the Histoire des populations et variation linguistique dans les Pyrénées de l'Ouest project, which received funding from the Conseil Régional d'Aquitaine, the Conseil Général des Pyrénées-Atlantiques, the Conseil des Elus du Pays-Basque, and the Centre National de la Recherche Scientifique interdisciplinary program Origine de l'Homme, des Langues et du Langage. This study also benefited from the support of Department of Hematology, Centre Hospitalier de la Côte Basque, in Bayonne, and Association Sang 64.