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Betz, J. F.

Publications and source records attributed to Betz, J. F..

2 recordsLinked to original sources

Accurate assignment of disease liability to genetic variants using only population data

PurposeThe growing size of public variant repositories prompted us to test the accuracy of predicting pathogenicity of DNA variants using population data alone. MethodsUnder the a priori assumption that the ratio of the prevalence of variants in healthy and affected populations form two distinct distributions (pathogenic and benign), we used a Bayesian method to assign probability of a variant belonging to either distribution. ResultsThe approach, termed BayPR, accurately parsed 300 of 313 expertly curated cystic fibrosis transmembrane conductance regulator (CFTR) variants: 284 of 296 pathogenic/likely pathogenic (P/LP) variants in one distribution and 16 of 17 benign/likely benign (B/LB) variants in another. BayPR produced an area under the receiver operating curve (AUC) of 0.99 for 103 functionally-confirmed missense CFTR variants, equal to or exceeding ten commonly used algorithms (AUC range: 0.54 to 0.99). Application of BayPR to expertly curated variants in eight genes associated with seven Mendelian conditions assigned [≥]80% disease-causing probability to 1,350 of 1,374 (98.3%) P/LP variants and [≤]20% to 22 of 23 (95.7%) B/LB variants. ConclusionAgnostic to variant type or functional effect, BayPR provides probabilities of pathogenicity for DNA variants responsible for Mendelian disorders using only variant counts in affected and unaffected population samples.

genetics↗

Commonly used insect repellents hide human odors from Anopheles mosquitoes

The mode of action for most mosquito repellents is unknown. This is primarily due to the difficulty in monitoring how the mosquito olfactory system responds to repellent odors. Here, we used the Q-system of binary expression to enable activity-dependent Ca2+ imaging in olfactory neurons of the African malaria mosquito Anopheles coluzzii. This system allows neuronal responses to common insect repellents to be directly visualized in living mosquitoes from all olfactory organs including the antenna. The synthetic repellents DEET and IR3535 did not activate Odorant Receptor Co-Receptor (Orco) expressing olfactory receptor neurons (ORNs) at any concentration, while picaridin weakly activated ORNs only at high concentrations. In contrast, natural repellents (i.e. lemongrass oil and eugenol) strongly activated small numbers of ORNs in the mosquito antennae at low concentrations. We determined that DEET, IR3535, and picaridin decrease the response of Orco expressing ORNs when these repellents are physically mixed with activating human-derived odorants. We present evidence that synthetic repellents may primarily exert their olfactory mode of action by decreasing the amount of activating ligand reaching ORNs. These results suggest that synthetic repellents disruptively change the chemical profile of host scent signatures on the skin surface rendering humans invisible to mosquitoes.

neuroscience↗