Department of Botany and Zoology, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic.
Radiat Res. 2019 Mar;191(3):255-261. doi: 10.1667/RR15208.1. Epub 2019 Jan 31.
It has been hypothesized that species with holocentric chromosomes have a selective evolutionary advantage for developmental and reproductive success because holocentric chromosomes are less susceptible to chromosome breakage than monocentric chromosomes. We analyzed data on sterilizing doses of ionizing radiation for more than 250 species of arthropods to test whether the minimal dose for reproductive sterilization is higher for species with holocentric chromosomes than for species with monocentric chromosomes. Using linear mixed models that account for phylogeny, we show that holocentric arthropods are more tolerant of sterilizing radiation than monocentrics. Moreover, higher dose rates correlate with lower sterilizing doses in monocentrics, but not in holocentrics, which is a novel finding that may be of importance for radiosanitation practice. Under the dose rate of 1 Gy/min, holocentric arthropods are sterilized on average with a 2.9 times higher minimal dose than monocentrics. Life stage and sex have significant but considerably weaker effects on sterilizing dose than chromosome type. Adults and males require 1.2 and 1.4 times higher sterilizing doses than juveniles and females, respectively. These results support the hypothesis that holocentric lineages may originate and thrive better in times of increased exposure to chromosome-breaking factors.
有人假设具有全着丝粒染色体的物种在发育和生殖成功方面具有选择进化优势，因为全着丝粒染色体比着丝粒染色体更不容易发生染色体断裂。我们分析了超过 250 种节肢动物的致死剂量电离辐射数据，以检验具有全着丝粒染色体的物种的生殖绝育最小剂量是否高于具有着丝粒染色体的物种。我们使用线性混合模型来解释进化关系，表明全着丝粒节肢动物比着丝粒节肢动物对绝育辐射更具有耐受性。此外，在着丝粒节肢动物中，更高的剂量率与更低的绝育剂量相关，而在全着丝粒节肢动物中则没有相关性，这是一个新的发现，对于放射卫生实践可能具有重要意义。在 1 Gy/min 的剂量率下，全着丝粒节肢动物的绝育最小剂量平均比着丝粒节肢动物高 2.9 倍。生活阶段和性别对绝育剂量的影响比染色体类型小得多，但仍然具有显著影响。与雌性相比，雄性和成年个体的绝育剂量分别比幼年个体高 1.2 倍和 1.4 倍。这些结果支持了这样的假设，即全着丝粒谱系在增加染色体断裂因素暴露的时期可能更容易起源和繁荣。
