Von Willebrand factor short sequence repeat locus 2 (intron 40) consists of three polymorphic subloci

Currently, identification of alleles within the short sequence repeat locus (SSR locus) of intron 40 of the von Willebrand factor gene (previously known as VNTR II) is based on the size of PCR products that only predicts a certain number of repeats. Through cloning and sequencing, we demonstrated the complexity of nucleotide sequence structure of this region by describing three polymorphic tetranucleotide repeat subloci SSR 'a', SSR 'b' and SSR 'c' within the same originally described locus: the original TCTA (9-14 repeats), a small TCTA repeat locus (2 or 3 repeats) located at the 5' end and 30 nucleotides upstream from the original locus and a TGTA repeat locus (5 or 6 repeats), adjacent to the 2/3 repeat locus. Sequencing of 54 VWF alleles has revealed 14 different sequence combinations in this region while the size variability in the region only amounts to a 7-allele system. While the determination of VNTR alleles by PCR remains a practical methodology in linkage analysis, this may not be applicable in forensic medicine since not all alleles of identical length based on PCR are the same. Our study reveals the important implication of the identification of SSR 2 subloci and concludes that at least in some situations, there may be a necessity to take into consideration these polymorphic subloc

Multi-messenger Observations of a Binary Neutron Star Merger

International audienceOn 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of $\sim 1.7\,{\rm{s}}$ with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg(2) at a luminosity distance of ${40}_{-8}^{+8}$ Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 $\,{M}_{\odot }$. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at $\sim 40\,{\rm{Mpc}}$) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position $\sim 9$ and $\sim 16$ days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta