University of South Alabama, Department of Mathematics and Statistics, Mobile, AL, United States of America.
Western Washington University, Department of Mathematics, Bellingham, WA, United States of America.
PLoS Comput Biol. 2019 Apr 22;15(4):e1006943. doi: 10.1371/journal.pcbi.1006943. eCollection 2019 Apr.
Genotypic variation, environmental variation, and their interaction may produce variation in the developmental process and cause phenotypic differences among individuals. Developmental noise, which arises during development from stochasticity in cellular and molecular processes when genotype and environment are fixed, also contributes to phenotypic variation. While evolutionary biology has long focused on teasing apart the relative contribution of genes and environment to phenotypic variation, our understanding of the role of developmental noise has lagged due to technical difficulties in directly measuring the contribution of developmental noise. The influence of developmental noise is likely underestimated in studies of phenotypic variation due to intrinsic mechanisms within organisms that stabilize phenotypes and decrease variation. Since we are just beginning to appreciate the extent to which phenotypic variation due to stochasticity is potentially adaptive, the contribution of developmental noise to phenotypic variation must be separated and measured to fully understand its role in evolution. Here, we show that variation in the component of the developmental process corresponding to environmental and genetic factors (here treated together as a unit called the LALI-type) versus the contribution of developmental noise, can be distinguished for leopard gecko (Eublepharis macularius) head color patterns using mathematical simulations that model the role of random variation (corresponding to developmental noise) in patterning. Specifically, we modified the parameters of simulations corresponding to variation in the LALI-type to generate the full range of phenotypic variation in color pattern seen on the heads of eight leopard geckos. We observed that over the range of these parameters, variation in color pattern due to LALI-type variation exceeds that due to developmental noise in the studied gecko cohort. However, the effect of developmental noise on patterning is also substantial. Our approach addresses one of the major goals of evolutionary biology: to quantify the role of stochasticity in shaping phenotypic variation.
基因型变异、环境变异及其相互作用可能会导致发育过程中的变异，并导致个体之间的表型差异。发育噪声是指在基因型和环境固定的情况下，细胞和分子过程中的随机性导致的发育过程中的变异，也会导致表型变异。尽管进化生物学长期以来一直致力于分离基因和环境对表型变异的相对贡献，但由于直接测量发育噪声贡献的技术困难，我们对发育噪声作用的理解一直滞后。由于生物体内部稳定表型并减少变异的内在机制，发育噪声的影响在表型变异研究中可能被低估。由于随机因素导致的表型变异可能具有适应性，因此我们才刚刚开始意识到这一点，因此必须分离和测量发育噪声对表型变异的贡献，以充分了解其在进化中的作用。在这里，我们通过数学模拟表明，对于豹纹变色龙（Eublepharis macularius）头部颜色图案，可以区分发育过程中对应于环境和遗传因素的组成部分（此处一起视为称为 LALI 型的单元）与发育噪声的贡献。具体来说，我们修改了模拟中对应于 LALI 型变异的参数，以产生在 8 只豹纹变色龙头部看到的颜色图案的全范围表型变异。我们观察到，在这些参数的范围内，由于 LALI 型变异引起的颜色图案变异大于在研究的变色龙群体中由于发育噪声引起的变异。然而，发育噪声对图案形成的影响也很大。我们的方法解决了进化生物学的主要目标之一：量化随机性在塑造表型变异中的作用。
