塔斯马尼亚恶魔产生了两个可传播的癌症品系，命名为DFT1和DFT2。
研究人员通过分析78个恶魔面部肿瘤1（DFT1）和41个恶魔面部肿瘤2（DFT2）的基因组与一个新组装的染色体水平的参照，研究了这些克隆的遗传多样性和演化。时间分辨的系统发育树显示，DFT1最早出现于1986年（1982年至1989年），DFT2出现于2011年（2009年至2012年）。亚克隆分析记录了异质性细胞群的传播。
DFT2在所有变异类别中的突变率都比DFT1快，包括替换、插入缺失、重排、转座元件插入和拷贝数改变，研究人员发现DFT1系的高突变率，有DNA错配修复缺陷。有几个位点显示了DFT1或DFT2中正向选择的合理证据，包括Y染色体的丢失和MGA的失活，但没有一个位点是两种癌症所共有的。这项研究揭示了居住在塔斯马尼亚袋獾共同生态位的两种可传播癌症的平行长期演化。
附：英文原文
Title: The evolution of two transmissible cancers in Tasmanian devils
Author: Maximilian R. Stammnitz, Kevin Gori, Young Mi Kwon, Edward Harry, Fergal J. Martin, Konstantinos Billis, Yuanyuan Cheng, Adrian Baez-Ortega, William Chow, Sebastien Comte, Hannes Eggertsson, Samantha Fox, Rodrigo Hamede, Menna Jones, Billie Lazenby, Sarah Peck, Ruth Pye, Michael A. Quail, Kate Swift, Jinhong Wang, Jonathan Wood, Kerstin Howe, Michael R. Stratton, Zemin Ning, Elizabeth P. Murchison
Issue&Volume: 2023-04-21
Abstract: Tasmanian devils have spawned two transmissible cancer lineages, named devil facial tumor 1 (DFT1) and devil facial tumor 2 (DFT2). We investigated the genetic diversity and evolution of these clones by analyzing 78 DFT1 and 41 DFT2 genomes relative to a newly assembled, chromosome-level reference. Time-resolved phylogenetic trees reveal that DFT1 first emerged in 1986 (1982 to 1989) and DFT2 in 2011 (2009 to 2012). Subclone analysis documents transmission of heterogeneous cell populations. DFT2 has faster mutation rates than DFT1 across all variant classes, including substitutions, indels, rearrangements, transposable element insertions, and copy number alterations, and we identify a hypermutated DFT1 lineage with defective DNA mismatch repair. Several loci show plausible evidence of positive selection in DFT1 or DFT2, including loss of chromosome Y and inactivation of MGA, but none are common to both cancers. This study reveals the parallel long-term evolution of two transmissible cancers inhabiting a common niche in Tasmanian devils.
DOI: abq6453
Source: https://www.science.org/doi/10.1126/science.abq6453