ORCID Profile
0000-0002-0788-0659
Current Organisations
University of Illinois Urbana-Champaign
,
University of Pennsylvania
,
Boston University
,
Harvard University
,
East Carolina University
,
National Science Foundation
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Publisher: Cold Spring Harbor Laboratory
Date: 11-02-2018
DOI: 10.1101/263913
Abstract: Birdsong is a classic ex le of a learned social behavior. Like many traits of interest, however, song production is also influenced by genetic factors and understanding the relative contributions of genetic and environmental influences remains a major research goal. In this study we take advantage of genetic variation among captive zebra finch populations to examine variation in a population-level song trait: song variability. We find that zebra finch populations differ in levels of song variability. Domesticated T. g. castanotis populations displayed higher song ersity than more recently wild-derived populations of both zebra finch subspecies T. g. castanotis and T. g. guttata , the Timor zebra finch. To determine whether these differences could have a genetic basis, we cross-fostered domesticated T. g. castanotis and Timor zebra finches to Bengalese finches Lonchura striata domestica . Following cross-fostering, domesticated T. g. castanotis maintained a higher level of song ersity than T. g. guttata . We suggest that the high song variability of domesticated zebra finches may be a consequence of reduced purifying selection acting on song traits. Intraspecific differences in the mechanisms underlying song variability therefore represent an untapped opportunity for probing the mechanisms of song learning and production.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 20-11-2015
Abstract: Multipotent Drosophila intestinal stem cells (ISCs) generate either nutrient-absorbing enterocytes (ECs) or secretory enteroendocrine cells (EECs). Guo and Ohlstein investigated the role of Notch signaling in this process. They tracked ISC asymmetric isions and found that EEC daughter cells, which have a low level of Notch, signal back to the ISC in order to keep it multipotent. However, during EC production, ISCs activate strong Notch signaling in daughters. Thus, Notch signaling functions in two directions to achieve stem cell multipotency. Science , this issue p. 10.1126/science.aab0988
Publisher: Springer Science and Business Media LLC
Date: 11-11-2020
Publisher: The Royal Society
Date: 05-2019
DOI: 10.1098/RSOS.190273
Abstract: Birdsong is a classic ex le of a learned social behaviour. Song behaviour is also influenced by genetic factors, and understanding the relative contributions of genetic and environmental influences remains a major goal. In this study, we take advantage of captive zebra finch populations to examine variation in a population-level song trait: song variability. Song variability is of particular interest in the context of in idual recognition and in terms of the neuro-developmental mechanisms that generate song novelty. We find that the Australian zebra finch Taeniopygia guttata castanotis ( TGC ) maintains higher song ersity than the Timor zebra finch T. g. guttata ( TGG ) even after experimentally controlling for early life song exposure, suggesting a genetic basis to this trait. Although wild-derived TGC were intermediate in song variability between domesticated TGC populations and TGG , the difference between domesticated and wild TGC was not statistically significant. The observed variation in song behaviour among zebra finch populations represents a largely untapped opportunity for exploring the mechanisms of social behaviour.
Publisher: Cold Spring Harbor Laboratory
Date: 23-05-2020
DOI: 10.1101/2020.05.22.110833
Abstract: High-quality and complete reference genome assemblies are fundamental for the application of genomics to biology, disease, and bio ersity conservation. However, such assemblies are only available for a few non-microbial species 1–4 . To address this issue, the international Genome 10K (G10K) consortium 5,6 has worked over a five-year period to evaluate and develop cost-effective methods for assembling the most accurate and complete reference genomes to date. Here we summarize these developments, introduce a set of quality standards, and present lessons learned from sequencing and assembling 16 species representing major vertebrate lineages (mammals, birds, reptiles, hibians, teleost fishes and cartilaginous fishes). We confirm that long-read sequencing technologies are essential for maximizing genome quality and that unresolved complex repeats and haplotype heterozygosity are major sources of error in assemblies. Our new assemblies identify and correct substantial errors in some of the best historical reference genomes. Adopting these lessons, we have embarked on the Vertebrate Genomes Project (VGP), an effort to generate high-quality, complete reference genomes for all ~70,000 extant vertebrate species and help enable a new era of discovery across the life sciences.
Publisher: Springer Science and Business Media LLC
Date: 28-04-2021
DOI: 10.1038/S41586-021-03451-0
Abstract: High-quality and complete reference genome assemblies are fundamental for the application of genomics to biology, disease, and bio ersity conservation. However, such assemblies are available for only a few non-microbial species 1–4 . To address this issue, the international Genome 10K (G10K) consortium 5,6 has worked over a five-year period to evaluate and develop cost-effective methods for assembling highly accurate and nearly complete reference genomes. Here we present lessons learned from generating assemblies for 16 species that represent six major vertebrate lineages. We confirm that long-read sequencing technologies are essential for maximizing genome quality, and that unresolved complex repeats and haplotype heterozygosity are major sources of assembly error when not handled correctly. Our assemblies correct substantial errors, add missing sequence in some of the best historical reference genomes, and reveal biological discoveries. These include the identification of many false gene duplications, increases in gene sizes, chromosome rearrangements that are specific to lineages, a repeated independent chromosome breakpoint in bat genomes, and a canonical GC-rich pattern in protein-coding genes and their regulatory regions. Adopting these lessons, we have embarked on the Vertebrate Genomes Project (VGP), an international effort to generate high-quality, complete reference genomes for all of the roughly 70,000 extant vertebrate species and to help to enable a new era of discovery across the life sciences.
Publisher: Springer Science and Business Media LLC
Date: 08-04-2021
DOI: 10.1038/S41586-021-03473-8
Abstract: A Correction to this paper has been published: 0.1038/s41586-021-03473-8.
Publisher: Cold Spring Harbor Laboratory
Date: 06-10-2022
DOI: 10.1101/2022.10.05.510848
Abstract: The neurogenomic mechanisms mediating male-male reproductive cooperative behaviors are unknown. We leveraged extensive transcriptomic and behavioral data on a neotropical bird ( Pipra filicauda ) that perform cooperative courtship displays to understand these mechanisms. Cooperative display is modulated by testosterone, it promotes cooperation in non-territorial birds, but suppresses cooperation in territory holders. We sought to understand the neurogenomic underpinnings of these three related traits: social status, cooperative behavior, and testosterone phenotype. To do this, we profiled gene expression in 10 brain nuclei spanning the social decision-making network (SDMN), and two key endocrine tissues that regulate social behavior. We associated gene expression with each bird’s behavioral and endocrine profile derived from 3 years of repeated measures taken from free-living birds in the Ecuadorian Amazon. We found distinct landscapes of constitutive gene expression were associated with social status, testosterone phenotype, and cooperation, reflecting the modular organization and engagement of neuroendocrine tissues. Sex-steroid and neuropeptide signaling appeared to be important in mediating status-specific relationships between testosterone and cooperation, suggesting shared regulatory mechanisms with male aggressive and sexual behaviors. We also identified differentially regulated genes involved in cellular activity and synaptic potentiation, suggesting multiple mechanisms underpin these genomic states. Finally, we identified SDMN-wide gene expression differences between territorial and floater males that could form the basis of “status-specific” neurophysiological phenotypes, potentially mediated by testosterone and growth hormone. Overall, our findings provide new, systems-level insights into the mechanisms of cooperative behavior and suggest that differences in neurogenomic state are the basis for in idual differences in social behavior.
Publisher: Springer Science and Business Media LLC
Date: 04-2010
DOI: 10.1038/NATURE08819
Publisher: Springer Science and Business Media LLC
Date: 04-2010
Location: United States of America
No related grants have been discovered for Christopher Balakrishnan.