Davison, C. | bioRxiv Science

bioRxiv2021

RBCeq: An Integrated Bioinformatics Algorithm Designed to Improve Blood Type Compatibility Testing

While blood transfusion is an essential cornerstone of hematological care, patients that require repetitive transfusion remain at persistent risk of alloimmunization due to the diversity of human blood group polymorphisms. Next-generation sequencing (NGS) is an effective means of identifying genotypic and phenotypic variations among the blood groups, while the accurate interpretation of such NGS data is currently hampered by a lack of accessibility to bioinformatics support. To address this unmet need, we have developed the RBCeq (https://www.rbceq.org/) platform, which consists of a novel bioinformatics algorithm coupled with a user-friendly web server capable of comprehensively delineating different blood group variants from genomics data with advanced visualization of results. The software profiles genomic data for 36 blood group systems, including two transcription factors and can identify small genetic alterations, including small indels and copy number variants. The RBCeq algorithm was validated on 403 samples which include 58 complex serology cases from Australian Red Cross LifeBlood, 100 samples from The MedSeq Project (phs000958) and a further 245 from Indigenous Australian participants. The final blood typing data from RBCeq was 99.83% concordant for 403 samples (85 different antigens in 21 blood group systems) with that listed from the International Society for Blood Transfusion database.

bioinformatics↗

bioRxiv2020

Slit2 is essential for correct retinal ganglion cell axon fasciculation and midline crossing in the zebrafish

Slit-Robo signaling has been implicated in regulating several steps of retinal ganglion cell axon guidance, with a central role assigned to Slit2. We report here the phenotypical characterization of a CRISPR-Cas9-generated zebrafish null mutant for this gene, along with a detailed analysis of its expression pattern by WM-FISH. All evident defects in the optic axons in slit2-/- mutants were detected outside the retina, coincident with the major sites of expression at the ventral forebrain, around the developing optic nerve and anterior to the optic chiasm/proximal tract. Anterograde axon tracing experiments in zygotic and maternal-zygotic mutants, as well as morphants, showed the occurrence of axon sorting defects, which appeared mild at the optic nerve level, but more severe in the optic chiasm and the proximal tract. A remarkable sorting defect was the usual splitting of one of the optic nerves in two branches that surrounded the contralateral nerve at the chiasm. Although all axons eventually crossed the midline, the retinotopic order appeared lost at the proximal optic tract, to eventually correct distally. Time-lapse analysis demonstrated the sporadic occurrence of axon misrouting at the chiasm level, which could be responsible for the sorting errors. Our results support previous evidence of a channeling role for Slit molecules in retinal ganglion cell axons at the optic nerve, in addition to a function in the segregation of axons coming from each nerve and from different retinal regions at the medio-ventral area of the forebrain.

developmental biology↗