Nicolas Betancourt - Academia.edu (original) (raw)
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Papers by Nicolas Betancourt
A fundamental aim of adaptation genomics is to identify polymorphisms that underpin variation in ... more A fundamental aim of adaptation genomics is to identify polymorphisms that underpin variation in fitness traits. In D. melanogaster latitudinal life-history clines exist on multiple continents and make an excellent system for dissecting the genetics of adaptation. We have previously identified numerous clinal SNPs in insulin/insulin-like growth factor signaling (IIS), a pathway known from mutant studies to affect life history. However, the effects of natural variants in this pathway remain poorly understood. Here we investigate how two clinal alternative alleles at foxo, a transcriptional effector of IIS, affect fitness components (viability, size, starvation resistance, fat content). We assessed this polymorphism from the North American cline by reconstituting outbred populations, fixed for either the low- or high-latitude allele, from inbred DGRP lines. Since diet and temperature modulate IIS, we phenotyped alleles across two temperatures (18C, 25C) and two diets differing in suga...
The insulin insulin-like growth factor signaling pathway has been hypothesized as a major determi... more The insulin insulin-like growth factor signaling pathway has been hypothesized as a major determinant of life history profiles that vary adaptively in natural populations. In Drosophila melanogaster, multiple components of this pathway vary predictably with latitude; this includes foxo, a conserved gene that regulates insulin signaling and has pleiotropic effects on a variety of fitness-associated traits. We hypothesized that allelic variation at foxo underlies genetic variance for traits that vary with latitude and reflect local adaptation. To evaluate this, we generated recombinant outbred populations in which the focal foxo allele was homozygous and fixed for either the allele common at high latitude or low latitude and the genomic background was randomized across 20 inbred lines. After eight generations of recombination, experimental populations were phenotyped for a series of traits related to gene function. Our results demonstrate that natural allelic variation at foxo has maj...
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2007
The charge collected from beta source particles in single pad detectors produced on p-type Magnet... more The charge collected from beta source particles in single pad detectors produced on p-type Magnetic Czochralski (MCz) silicon wafers has been measured before and after irradiation with 26 MeV protons. After a 1 MeV neutron equivalent fluence of 1 Â 10 15 cm À2 the collected charge is reduced to 77% at bias voltages below 900 V. This result is compared with previous results from charge collection measurements. r 2007 Published by Elsevier B.V. (M. Bruzzi).
Nicolás Betancourt , 2021
A fundamental aim of adaptation genomics is to identify polymorphisms that underpin variation in ... more A fundamental aim of adaptation genomics is to identify polymorphisms that underpin variation in fitness traits. In D. melanogaster latitudinal life-history clines exist on multiple continents and make an excellent system for dissecting the genetics of adaptation. We have previously identified numerous clinal SNPs in insulin/insulin-like growth factor signaling (IIS), a pathway known from mutant studies to affect life history. However, the effects of natural variants in this pathway remain poorly understood. Here we investigate how two clinal alternative alleles at foxo, a transcriptional effector of IIS, affect fitness components (viability, size, starvation resistance, fat content). We assessed this polymorphism from the North American cline by reconstituting outbred populations, fixed for either the low- or high-latitude allele, from inbred DGRP lines. Since diet and temperature modulate IIS, we phenotyped alleles across two temperatures (18C, 25C) and two diets differing in suga...
The insulin insulin-like growth factor signaling pathway has been hypothesized as a major determi... more The insulin insulin-like growth factor signaling pathway has been hypothesized as a major determinant of life history profiles that vary adaptively in natural populations. In Drosophila melanogaster, multiple components of this pathway vary predictably with latitude; this includes foxo, a conserved gene that regulates insulin signaling and has pleiotropic effects on a variety of fitness-associated traits. We hypothesized that allelic variation at foxo underlies genetic variance for traits that vary with latitude and reflect local adaptation. To evaluate this, we generated recombinant outbred populations in which the focal foxo allele was homozygous and fixed for either the allele common at high latitude or low latitude and the genomic background was randomized across 20 inbred lines. After eight generations of recombination, experimental populations were phenotyped for a series of traits related to gene function. Our results demonstrate that natural allelic variation at foxo has maj...
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2007
The charge collected from beta source particles in single pad detectors produced on p-type Magnet... more The charge collected from beta source particles in single pad detectors produced on p-type Magnetic Czochralski (MCz) silicon wafers has been measured before and after irradiation with 26 MeV protons. After a 1 MeV neutron equivalent fluence of 1 Â 10 15 cm À2 the collected charge is reduced to 77% at bias voltages below 900 V. This result is compared with previous results from charge collection measurements. r 2007 Published by Elsevier B.V. (M. Bruzzi).
Nicolás Betancourt , 2021