Babies of South Asian and European Ancestry Show Similar Associations With Genetic Risk Score for Birth Weight Despite the Smaller Size of South Asian Newborns.

Size at birth is known to be influenced by various fetal and maternal factors, including genetic effects. South Asians have a high burden of low birth weight and cardiometabolic diseases, yet studies of common genetic variations underpinning these phenotypes are lacking. We generated independent, weighted fetal genetic scores (fGSs) and maternal genetic scores (mGSs) from 196 birth weight-associated variants identified in Europeans and conducted an association analysis with various fetal birth parameters and anthropometric and cardiometabolic traits measured at different follow-up stages (5-6-year intervals) from seven Indian and Bangladeshi cohorts of South Asian ancestry. The results from these cohorts were compared with South Asians in UK Biobank and the Exeter Family Study of Childhood Health, a European ancestry cohort. Birth weight increased by 50.7 g and 33.6 g per SD of fGS (P = 9.1 × 10-11) and mGS (P = 0.003), respectively, in South Asians. A relatively weaker mGS effect compared with Europeans indicates possible different intrauterine exposures between Europeans and South Asians. Birth weight was strongly associated with body size in both childhood and adolescence (P = 3 × 10-5 to 1.9 × 10-51); however, fGS was associated with body size in childhood only (P < 0.01) and with head circumference, fasting glucose, and triglycerides in adults (P < 0.01). The substantially smaller newborn size in South Asians with comparable fetal genetic effect to Europeans on birth weight suggests a significant role of factors related to fetal growth that were not captured by the present genetic scores. These factors may include different environmental exposures, maternal body size, health and nutritional status, etc. Persistent influence of genetic loci on size at birth and adult metabolic syndrome in our study supports a common genetic mechanism that partly explains associations between early development and later cardiometabolic health in various populations, despite marked differences in phenotypic and environmental factors in South Asians

Applications of CRISPR–Cas systems in neuroscience

Genome-editing tools, and in particular those based on CRISPR-Cas (clustered regularly interspaced short palindromic repeat (CRISPR)-CRISPR-associated protein) systems, are accelerating the pace of biological research and enabling targeted genetic interrogation in almost any organism and cell type. These tools have opened the door to the development of new model systems for studying the complexity of the nervous system, including animal models and stem cell-derived in vitro models. Precise and efficient gene editing using CRISPR-Cas systems has the potential to advance both basic and translational neuroscience research.National Institute of Mental Health (U.S.) (Grant 5DP1-MH100706)National Institute of Mental Health (U.S.) (Grant 1R01-MH110049)National Institute of Diabetes and Digestive and Kidney Diseases (U.S.) (Grant 5R01DK097768-03

Efficient genetic manipulation of the NOD-Rag1-/-IL2RgammaC-null mouse by combining in vitro fertilization and CRISPR/Cas9 technology

Humanized mouse models have become increasingly important and widely used in modeling human diseases in biomedical research. Immunodeficient mice such as NOD-Rag1-/-IL2RgammaC-null (NRG) or NOD-SCID-IL2RgammaC-null (NSG) mice are critical for efficient engraftment of human cells or tissues. However, their genetic modification remains challenging due to a lack of embryonic stem cells and difficulty in the collection of timed embryos after superovulation. Here, we report the generation of gene knockout NRG mice by combining in vitro fertilization (IVF) and CRISPR/Cas9 technology. Sufficient numbers of fertilized embryos were produced through IVF, and a high rate of Fah gene targeting was achieved with microinjection of Cas9 mRNA, gRNA and single strand oligonucleotide DNA (ssDNA) into the embryos. The technology paves the way to construct NRG or NSG mutant mice to facilitate new humanized mouse models. The technology can also be readily adapted to introduce mutations in other species such as swine and non-human primates