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Telomere length is highly heritable and independent of growth rate manipulated by temperature in field crickets
bioRxiv - Zoology Pub Date : 2020-05-31 , DOI: 10.1101/2020.05.29.123216
Jelle Boonekamp , Rolando Rodríguez-Muñoz , Paul Hopwood , Erica Zuidersma , Ellis Mulder , Alastair Wilson , Simon Verhulst , Tom Tregenza

Many organisms are capable of growing faster than they do. Restrained growth rate has functionally been explained by negative effects on lifespan of accelerated growth. However, the underlying mechanisms remain elusive. Telomere attrition has been proposed as a causal agent and has been studied in endothermic vertebrates. We established that telomeres exist as chromosomal-ends in a model insect, the field cricket, using terminal restriction fragment and Bal 31 methods. Telomeres comprised TTAGGn repeats of 38kb on average, more than four times longer than the telomeres of human infants. Bal 31 assays confirmed that telomeric repeats were located at the chromosome-ends. We tested whether rapid growth is achieved at the expense of telomere length by comparing crickets reared at 23°C with their siblings reared at 28°C, which grew three times faster. Surprisingly, neither temperature treatment nor age affected average telomere length. Concomitantly, the broad sense heritability of telomere length was remarkably high at ~100%. Despite high heritability, the evolvability (a mean standardized measure of genetic variance) was low relative to that of body mass. We discuss the different interpretations of these scaling methods in the context of telomere evolution. It is clear that some important features of vertebrate telomere biology are evident in an insect species dating back to the Triassic, but also that there are some striking differences. The apparent lack of an effect of growth rate and the total number of cell divisions on telomere length is puzzling, suggesting that telomere length could be actively maintained during the growth phase. Whether such maintenance of telomere length is adaptive remains elusive and requires further study investigating the links with fitness in the wild.

中文翻译:

端粒的长度是高度可遗传的,并且与field的温度控制的生长速率无关

许多生物的生长能力比它们快。抑制生长速率的功能可以解释为对加速生长寿命的负面影响。但是,基本机制仍然难以捉摸。端粒耗损已被认为是病因,并且已经在吸热脊椎动物中进行了研究。我们使用末端限制片段和Bal 31方法建立了端粒作为昆虫模型,的染色体末端存在。端粒平均包含38kb的TTAGGn重复序列,是人类婴儿端粒的四倍以上。Bal 31分析证实端粒重复位于染色体末端。通过比较23在23°C饲养的with与兄弟姐妹在28°C饲养的grew的生长速度,该rapid生长快了三倍,从而测试了是否以端粒长度为代价实现了快速生长。出人意料的是,温度处理和年龄均不影响平均端粒长度。同时,端粒长度的广义遗传力非常高,约为100%。尽管遗传力很高,但进化力(遗传变异的平均标准化度量)相对于体重而言却很低。我们讨论了端粒进化过程中这些缩放方法的不同解释。很明显,脊椎动物端粒生物学的一些重要特征在可追溯到三叠纪的昆虫物种中很明显,但也存在一些惊人的差异。端粒长度明显缺乏生长速率和细胞分裂总数的影响令人费解,这表明端粒长度可以在生长期积极维持。
更新日期:2020-05-31
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