Loss-of-heterozygosity facilitates a fitness valley crossing in experimentally evolved multicellular yeast.
Loss-of-heterozygosity facilitates a fitness valley crossing in experimentally evolved multicellular yeast.
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DOI：
10.1098/rspb.2021.2722
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发表时间：
2022-06-08
影响因子：
4.7
通讯作者：
Travisano, Michael
中科院分区：
文献类型：
--
作者：
Baselga-Cervera, Beatriz;Gettle, Noah;Travisano, Michael
关键词：
确定适应性可能性如何成为或不成为进化现实对于理解进化变化的节奏和模式至关重要。一些最简单的进化景观源于单个位点的优势不足，其中适应度谷仅由一种不太适合的基因型组成。尽管它们具有快速进化变化的潜力，但很少有这样的例子被研究过。我们利用了一个实验系统，在该系统中，在通过实验选择以提高沉降率的酿酒酵母无性二倍体群体中观察到了显着的进化转变，即从单细胞到多细胞的转变。多细胞表型是由经历杂合性丢失（LOH）事件的隐性单基因座突变引起的。通过重建必要的杂合中间步骤，我们发现多细胞的进化涉及第一步中尺寸的减小。杂合基因型的大小比具有功能等位基因的基因型小 20%。然而，通过快速的LOH事件，杂合子群体比具有两个功能等位基因的单细胞基因型更容易产生多细胞基因型。 LOH 驱动适应，可能使二倍体酵母能够快速进化。这些结果共同表明表型和基因型多细胞转变之间的不一致。多细胞的进化路径以及增加体型带来的适应性好处需要初始体型的减小。
Determining how adaptive possibilities do or do not become evolutionary realities is central to understanding the tempo and mode of evolutionary change. Some of the simplest evolutionary landscapes arise from underdominance at a single locus where the fitness valley consists of only one less-fit genotype. Despite their potential for rapid evolutionary change, few such examples have been investigated. We capitalized on an experimental system in which a significant evolutionary shift, the transition from uni-to-multicellularity, was observed in asexual diploid populations of Saccharomyces cerevisiae experimentally selected for increased settling rates. The multicellular phenotype results from recessive single-locus mutations that undergo loss-of-heterozygosity (LOH) events. By reconstructing the necessary heterozygous intermediate steps, we found that the evolution of multicellularity involves a decrease in size during the first steps. Heterozygous genotypes are 20% smaller in size than genotypes with functional alleles. Nevertheless, populations of heterozygotes give rise to multicellular genotypes more readily than unicellular genotypes with two functional alleles, by rapid LOH events. LOH drives adaptation that may enable rapid evolution in diploid yeast. Together these results show discordance between the phenotypic and genotypic multicellular transition. The evolutionary path to multicellularity, and the adaptive benefits of increased size, requires initial size reductions.
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影响因子：
14.8
作者：
Gietz, R. Daniel;Schiestl, Robert H.
通讯作者：
Schiestl, Robert H.
影响因子：
10.7
作者：
Smukowski Heil CS;DeSevo CG;Pai DA;Tucker CM;Hoang ML;Dunham MJ
通讯作者：
Dunham MJ
影响因子：
16.6
作者：
Gerstein, A. C.;Kuzmin, A.;Otto, S. P.
通讯作者：
Otto, S. P.
影响因子：
2
作者：
Davis, S;Bax, N;Grewe, P
通讯作者：
Grewe, P
DOI：
10.1098/rspb.1979.0086
发表时间：
1979-01-01
期刊：
PROCEEDINGS OF THE ROYAL SOCIETY SERIES B-BIOLOGICAL SCIENCES
影响因子：
--
作者：
GOULD, SJ;LEWONTIN, RC
通讯作者：
LEWONTIN, RC