Department of Biological and Environmental Science, University of Jyväskylä, 40014, Jyväskylä, Finland.
Sci Rep. 2024 May 28;14(1):12162. doi: 10.1038/s41598-024-63030-x.
Many fisheries exert directional selection on traits such as body size and growth rate. Whether directional selection impacts regions of the genome associated with traits related to growth is unknown. To address this issue, we characterised copy number variation in three regions of the genome associated with cell division, (1) telomeric DNA, (2) loci transcribed as ribosomal RNA (rDNA), and (3) mitochondrial DNA (mtDNA), in three selection lines of zebrafish reared at three temperatures (22 °C, 28 °C, and 34 °C). Selection lines differed in (1) the direction of selection (two lines experienced directional selection for large or small body size) and (2) whether they experienced any directional selection itself. Lines that had experienced directional selection were smaller, had lower growth rate, shorter telomeres, and lower rDNA copy number than the line that experiencing no directional selection. Neither telomere length nor rDNA copy number were affected by temperature. In contrast, mtDNA content increased at elevated temperature but did not differ among selection lines. Though directional selection impacts rDNA and telomere length, direction of such selection did not matter, whereas mtDNA acts as a stress marker for temperature. Future work should examine the consequences of these genomic changes in natural fish stocks.
许多渔业对体型和生长速度等特征施加定向选择。定向选择是否会影响与生长相关的性状相关的基因组区域尚不清楚。为了解决这个问题，我们在三个温度（22°C、28°C 和 34°C）下培养的三个斑马鱼选择系中，对与细胞分裂相关的三个基因组区域（1）端粒 DNA、（2）转录为核糖体 RNA（rDNA）的基因座和（3）线粒体 DNA（mtDNA）的拷贝数变异进行了特征描述。选择系在（1）选择的方向（两个系经历了对大或小体型的定向选择）和（2）它们自身是否经历了任何定向选择方面存在差异。经历了定向选择的系比没有经历定向选择的系体型更小、生长速度更慢、端粒更短、rDNA 拷贝数更低。温度对端粒长度或 rDNA 拷贝数没有影响。相比之下，mtDNA 含量在高温下增加，但在选择系之间没有差异。虽然定向选择会影响 rDNA 和端粒长度，但选择的方向并不重要，而 mtDNA 是温度的应激标志物。未来的工作应该研究这些基因组变化对自然鱼类种群的影响。
