研究人员对241个胎生哺乳动物基因组的排列组合进行了全面的系统发育分析，并解决了以前对跨物种基因组采样有限的担忧。研究人员使用连接和基于凝聚的方法比较了中性的全基因组系统发育信号，询问了跨染色体的系统发育变异，并分析了大量的结构变异目录。
在不同的数据集和分析方法中，脊柱间关系表现出相对较低的系统发育冲突率。相反，X染色体与常染色体的冲突是新生代辐射的多个独立支系的特征。基因组时间树显示，在白垩纪-古近纪（K-Pg）边界之前和紧接着之后，有大量的支系发生，这意味着白垩纪大陆迁移和K-Pg灭绝在胎盘辐射中发挥了重要作用。
研究人员表示，产生所有活体胎盘哺乳动物的精确模式和时间仍有争议。
附：英文原文
Title: A genomic timescale for placental mammal evolution
Author: Nicole M. Foley, Victor C. Mason, Andrew J. Harris, Kevin R. Bredemeyer, Joana Damas, Harris A. Lewin, Eduardo Eizirik, John Gatesy, Elinor K. Karlsson, Kerstin Lindblad-Toh, Zoonomia Consortium, Mark S. Springer, William J. Murphy, Gregory Andrews, Joel C. Armstrong, Matteo Bianchi, Bruce W. Birren, Kevin R. Bredemeyer, Ana M. Breit, Matthew J. Christmas, Hiram Clawson, Joana Damas, Federica Di Palma, Mark Diekhans, Michael X. Dong, Eduardo Eizirik, Kaili Fan, Cornelia Fanter, Nicole M. Foley, Karin Forsberg-Nilsson, Carlos J. Garcia, John Gatesy, Steven Gazal, Diane P. Genereux, Linda Goodman, Jenna Grimshaw, Michaela K. Halsey, Andrew J. Harris, Glenn Hickey, Michael Hiller, Allyson G. Hindle, Robert M. Hubley, Graham M. Hughes, Jeremy Johnson, David Juan, Irene M. Kaplow, Elinor K. Karlsson, Kathleen C. Keough, Bogdan Kirilenko, Klaus-Peter Koepfli, Jennifer M. Korstian, Amanda Kowalczyk, Sergey V. Kozyrev, Alyssa J. Lawler, Colleen Lawless, Thomas Lehmann, Danielle L. Levesque, Harris A. Lewin, Xue Li, Abigail Lind, Kerstin Lindblad-Toh, Ava Mackay-Smith, Voichita D. Marinescu, Tomas Marques-Bonet, Victor C. Mason, Jennifer R. S. Meadows, Wynn K. Meyer, Jill E. Moore, Lucas R. Moreira, Diana D. Moreno-Santillan, Kathleen M. Morrill, Gerard Muntané, William J. Murphy, Arcadi Navarro, Martin Nweeia, Sylvia Ortmann, Austin Osmanski, Benedict Paten, Nicole S. Paulat, Andreas R. Pfenning, BaDoi N. Phan, Katherine S. Pollard, Henry E. Pratt, David A. Ray, Steven K. Reilly, Jeb R. Rosen, Irina Ruf, Louise Ryan, Oliver A. Ryder, Pardis C. Sabeti, Daniel E. Schffer, Aitor Serres, Beth Shapiro, Arian F. A. Smit, Mark Springer, Chaitanya Srinivasan, Cynthia Steiner, Jessica M. Storer, Kevin A. M. Sullivan, Patrick F. Sullivan, Elisabeth Sundstrm, Megan A. Supple, Ross Swofford, Joy-El Talbot, Emma Teeling, Jason Turner-Maier, Alejandro Valenzuela, Franziska Wagner, Ola Wallerman, Chao Wang, Juehan Wang, Zhiping Weng, Aryn P. Wilder, Morgan E. Wirthlin, James R. Xue, Xiaomeng Zhang
Issue&Volume: 2023-04-28
Abstract: The precise pattern and timing of speciation events that gave rise to all living placental mammals remain controversial. We provide a comprehensive phylogenetic analysis of genetic variation across an alignment of 241 placental mammal genome assemblies, addressing prior concerns regarding limited genomic sampling across species. We compared neutral genome-wide phylogenomic signals using concatenation and coalescent-based approaches, interrogated phylogenetic variation across chromosomes, and analyzed extensive catalogs of structural variants. Interordinal relationships exhibit relatively low rates of phylogenomic conflict across diverse datasets and analytical methods. Conversely, X-chromosome versus autosome conflicts characterize multiple independent clades that radiated during the Cenozoic. Genomic time trees reveal an accumulation of cladogenic events before and immediately after the Cretaceous-Paleogene (K-Pg) boundary, implying important roles for Cretaceous continental vicariance and the K-Pg extinction in the placental radiation.
DOI: abl8189
Source: https://www.science.org/doi/10.1126/science.abl8189