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Sadier A, Anthwal N, Krause AL, Dessalles R, Lake M, Bentolila LA, Haase R, Nieves NA, Santana SE, Sears KE. Bat teeth illuminate the diversification of mammalian tooth classes. Nat Commun 2023; 14:4687. [PMID: 37607943 PMCID: PMC10444822 DOI: 10.1038/s41467-023-40158-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 07/11/2023] [Indexed: 08/24/2023] Open
Abstract
Tooth classes are an innovation that has contributed to the evolutionary success of mammals. However, our understanding of the mechanisms by which tooth classes diversified remain limited. We use the evolutionary radiation of noctilionoid bats to show how the tooth developmental program evolved during the adaptation to new diet types. Combining morphological, developmental and mathematical modeling approaches, we demonstrate that tooth classes develop through independent developmental cascades that deviate from classical models. We show that the diversification of tooth number and size is driven by jaw growth rate modulation, explaining the rapid gain/loss of teeth in this clade. Finally, we mathematically model the successive appearance of tooth buds, supporting the hypothesis that growth acts as a key driver of the evolution of tooth number and size. Our work reveal how growth, by tinkering with reaction/diffusion processes, drives the diversification of tooth classes and other repeated structure during adaptive radiations.
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Affiliation(s)
- Alexa Sadier
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA, USA.
| | - Neal Anthwal
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA, USA
- Centre for Craniofacial and Regenerative Biology, King's College London, London, UK
| | | | - Renaud Dessalles
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA, USA
- Greenshield, 46 rue Saint-Antoine, 75004, Paris, France
| | - Michael Lake
- Advanced Light Microscopy and Spectroscopy Laboratory, California NanoSystems Institute, UCLA, Los Angeles, CA, 90095, USA
| | - Laurent A Bentolila
- Advanced Light Microscopy and Spectroscopy Laboratory, California NanoSystems Institute, UCLA, Los Angeles, CA, 90095, USA
| | - Robert Haase
- DFG Cluster of Excellence "Physics of Life", TU Dresden, Dresden, Germany
| | - Natalie A Nieves
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA, USA
| | - Sharlene E Santana
- Department of Biology and Burke Museum of Natural History and Culture, University of Washington, Seattle, WA, USA
| | - Karen E Sears
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA, USA.
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Wang Y, Dessalles R, Chou T. Modelling the impact of birth control policies on China's population and age: effects of delayed births and minimum birth age constraints. R Soc Open Sci 2022. [PMID: 35706677 DOI: 10.5281/zenodo.6394805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
We consider age-structured models with an imposed refractory period between births. These models can be used to formulate alternative population control strategies to China's one-child policy. By allowing any number of births, but with an imposed delay between births, we show how the total population can be decreased and how a relatively older age distribution can be generated. This delay represents a more 'continuous' form of population management for which the strict one-child policy is a limiting case. Such a policy approach could be more easily accepted by society. Our analyses provide an initial framework for studying demographics and how social constraints influence population structure.
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Affiliation(s)
- Yue Wang
- Department of Computational Medicine, UCLA, Los Angeles, CA 90095-1766, USA
| | | | - Tom Chou
- Department of Computational Medicine, UCLA, Los Angeles, CA 90095-1766, USA
- Department of Mathematics, UCLA, Los Angeles, CA 90095-1555, USA
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Wang Y, Dessalles R, Chou T. Modelling the impact of birth control policies on China's population and age: effects of delayed births and minimum birth age constraints. R Soc Open Sci 2022; 9:211619. [PMID: 35706677 PMCID: PMC9174737 DOI: 10.1098/rsos.211619] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 05/16/2022] [Indexed: 05/03/2023]
Abstract
We consider age-structured models with an imposed refractory period between births. These models can be used to formulate alternative population control strategies to China's one-child policy. By allowing any number of births, but with an imposed delay between births, we show how the total population can be decreased and how a relatively older age distribution can be generated. This delay represents a more 'continuous' form of population management for which the strict one-child policy is a limiting case. Such a policy approach could be more easily accepted by society. Our analyses provide an initial framework for studying demographics and how social constraints influence population structure.
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Affiliation(s)
- Yue Wang
- Department of Computational Medicine, UCLA, Los Angeles, CA 90095-1766, USA
| | | | - Tom Chou
- Department of Computational Medicine, UCLA, Los Angeles, CA 90095-1766, USA
- Department of Mathematics, UCLA, Los Angeles, CA 90095-1555, USA
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Dessalles R, Pan Y, Xia M, Maestrini D, D'Orsogna MR, Chou T. How Naive T-Cell Clone Counts Are Shaped By Heterogeneous Thymic Output and Homeostatic Proliferation. Front Immunol 2022; 12:735135. [PMID: 35250963 PMCID: PMC8891377 DOI: 10.3389/fimmu.2021.735135] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 12/06/2021] [Indexed: 11/13/2022] Open
Abstract
The specificity of T cells is that each T cell has only one T cell receptor (TCR). A T cell clone represents a collection of T cells with the same TCR sequence. Thus, the number of different T cell clones in an organism reflects the number of different T cell receptors (TCRs) that arise from recombination of the V(D)J gene segments during T cell development in the thymus. TCR diversity and more specifically, the clone abundance distribution, are important factors in immune functions. Specific recombination patterns occur more frequently than others while subsequent interactions between TCRs and self-antigens are known to trigger proliferation and sustain naive T cell survival. These processes are TCR-dependent, leading to clone-dependent thymic export and naive T cell proliferation rates. We describe the heterogeneous steady-state population of naive T cells (those that have not yet been antigenically triggered) by using a mean-field model of a regulated birth-death-immigration process. After accounting for random sampling, we investigate how TCR-dependent heterogeneities in immigration and proliferation rates affect the shape of clone abundance distributions (the number of different clones that are represented by a specific number of cells, or “clone counts”). By using reasonable physiological parameter values and fitting predicted clone counts to experimentally sampled clone abundances, we show that realistic levels of heterogeneity in immigration rates cause very little change to predicted clone-counts, but that modest heterogeneity in proliferation rates can generate the observed clone abundances. Our analysis provides constraints among physiological parameters that are necessary to yield predictions that qualitatively match the data. Assumptions of the model and potentially other important mechanistic factors are discussed.
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Affiliation(s)
- Renaud Dessalles
- Department of Computational Medicine, University of California at Los Angeles (UCLA), Los Angeles, CA, United States
| | - Yunbei Pan
- Department of Mathematics, California State University at Northridge, Los Angeles, CA, United States
| | - Mingtao Xia
- Department of Mathematics, University of California at Los Angeles (UCLA), Los Angeles, CA, United States
| | - Davide Maestrini
- Department of Computational Medicine, University of California at Los Angeles (UCLA), Los Angeles, CA, United States
| | - Maria R D'Orsogna
- Department of Computational Medicine, University of California at Los Angeles (UCLA), Los Angeles, CA, United States.,Department of Mathematics, California State University at Northridge, Los Angeles, CA, United States
| | - Tom Chou
- Department of Computational Medicine, University of California at Los Angeles (UCLA), Los Angeles, CA, United States.,Department of Mathematics, University of California at Los Angeles (UCLA), Los Angeles, CA, United States
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Dessalles R, Fromion V, Robert P. Models of protein production along the cell cycle: An investigation of possible sources of noise. PLoS One 2020; 15:e0226016. [PMID: 31945071 PMCID: PMC6964835 DOI: 10.1371/journal.pone.0226016] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 11/18/2019] [Indexed: 01/20/2023] Open
Abstract
In this article, we quantitatively study, through stochastic models, the effects of several intracellular phenomena, such as cell volume growth, cell division, gene replication as well as fluctuations of available RNA polymerases and ribosomes. These phenomena are indeed rarely considered in classic models of protein production and no relative quantitative comparison among them has been performed. The parameters for a large and representative class of proteins are determined using experimental measures. The main important and surprising conclusion of our study is to show that despite the significant fluctuations of free RNA polymerases and free ribosomes, they bring little variability to protein production contrary to what has been previously proposed in the literature. After verifying the robustness of this quite counter-intuitive result, we discuss its possible origin from a theoretical view, and interpret it as the result of a mean-field effect.
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Affiliation(s)
- Renaud Dessalles
- Dept. of Biomathematics, UCLA, Los Angeles, CA, United States of America
| | - Vincent Fromion
- MaIAGE, INRA, Université Paris-Saclay, Jouy-en-Josas, France
- * E-mail:
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