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挪威奥斯陆大学Walter Salzburger和瑞士巴塞尔大学Fabrizia Ronco小组合作在研究中取得进展。他们揭示了慈鲷科鱼类体内大量适应性辐射的诱导因素和动力学。该项研究成果在线发表在2020年11月18日出版的《自然》杂志上。

研究人员对坦噶尼喀湖中慈鲷科鱼类适应性辐射进行了深入的研究。在全基因组系统发育分析的基础上，研究人员对坦噶尼喀湖中约240个慈鲷科品种的三个与生态相关的性状复合体（体形、上颌颌形态和下咽咽形态）进行了多变量形态学测量、色素沉着模式评估和生态学近似值确定，表明辐射发生在湖区范围内，并且形态的多样化始于连续特定性状的空间扩展脉冲。

研究为自适应辐射如何进行的两个理论预测提供了数据支持，即“早期爆发”时期（针对身体形状）和阶段模型（针对所研究的所有特征）。通过分析每个物种的两个基因组，并利用辐射区域中物种的不均匀分布，研究进一步表明物种丰富度与每个个体的杂合度成正相关，但与转座因子含量、基因重复或全基因组水平编码序列的选择无关。

据悉，适应性辐射是生命体中许多生态和形态多样性的可能来源。在大多数情况下，尚不清楚自适应辐射如何进行以及如何决定其辐射范围。

附：英文原文

Title: Drivers and dynamics of a massive adaptive radiation in cichlid fishes

Author: Fabrizia Ronco, Michael Matschiner, Astrid Bhne, Anna Boila, Heinz H. Bscher, Athimed El Taher, Adrian Indermaur, Milan Malinsky, Virginie Ricci, Ansgar Kahmen, Sissel Jentoft, Walter Salzburger

Issue&Volume: 2020-11-18

Abstract: Adaptive radiation is the likely source of much of the ecological and morphological diversity of life1,2,3,4. How adaptive radiations proceed and what determines their extent remains unclear in most cases1,4. Here we report the in-depth examination of the spectacular adaptive radiation of cichlid fishes in Lake Tanganyika. On the basis of whole-genome phylogenetic analyses, multivariate morphological measurements of three ecologically relevant trait complexes (body shape, upper oral jaw morphology and lower pharyngeal jaw shape), scoring of pigmentation patterns and approximations of the ecology of nearly all of the approximately 240 cichlid species endemic to Lake Tanganyika, we show that the radiation occurred within the confines of the lake and that morphological diversification proceeded in consecutive trait-specific pulses of rapid morphospace expansion. We provide empirical support for two theoretical predictions of how adaptive radiations proceed, the ‘early-burst’ scenario1,5 (for body shape) and the stages model1,6,7 (for all traits investigated). Through the analysis of two genomes per species and by taking advantage of the uneven distribution of species in subclades of the radiation, we further show that species richness scales positively with per-individual heterozygosity, but is not correlated with transposable element content, number of gene duplications or genome-wide levels of selection in coding sequences.

DOI: 10.1038/s41586-020-2930-4

Source: https://www.nature.com/articles/s41586-020-2930-4

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