Nieves Mariela, Puntieri Fiona, Bailey Susan M, Mudry Marta D, Maranon David G
Centro de Investigación en Reproducción Humana y Experimental (CIRHE), Centro de Educación Médica e Investigaciones Clínicas (CEMIC), CONICET, Buenos Aires C1431-CABA, Argentina.
Grupo de Investigación en Biología Evolutiva (GIBE), Departamento de Ecología, Genética y Evolución (DEGE), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires C1428-CABA, Argentina.
Animals (Basel). 2023 Feb 1;13(3):510. doi: 10.3390/ani13030510.
There are extensive studies on chromosome morphology and karyotype diversity in primates, yet we still lack insight into genomic instability as a key factor underlying the enormous interspecies chromosomal variability and its potential contribution to evolutionary dynamics. In this sense, the assessment of spontaneous sister chromatid exchange (SCE) frequencies represents a powerful tool for evaluating genome stability. Here, we employed G-banding, fluorescence plus Giemsa (FPG), and chromosome orientation fluorescence in situ hybridization (CO-FISH) methodologies to characterize both chromosome-specific frequencies of spontaneously occurring SCE throughout the genome (G-SCE) and telomere-specific SCE (T-SCE). We analyzed primary fibroblast cultures from two male species of living in captivity: (APA) and (ACH). High frequencies of G-SCEs were observed in both species. Interestingly, G-SCEs clustered on evolutionary relevant chromosome pairs: ACH chromosomes 1, 2, 3, 4, and 7, and APA chromosomes 1, 2, 3, 4/12, 7, and 10. Furthermore, a statistically significant difference between the observed and expected G-SCE frequencies, not correlated with chromosome size, was also detected. CO-FISH analyses revealed the presence of telomere-specific recombination events in both species, which included T-SCE, as well as interstitial telomere signals and telomere duplications, with APA chromosomes displaying higher frequencies, compared to ACH. Our analyses support the hypothesis that regions of chromosomes susceptible to recombination events are fragile sites and evolutionary hot spots. Thus, we propose SCE analyses as a valuable indicator of genome instability in non-human primates.
关于灵长类动物染色体形态和核型多样性已有广泛研究，但我们仍缺乏对基因组不稳定性的深入了解，而基因组不稳定性是物种间巨大染色体变异性的关键因素及其对进化动态潜在贡献的基础。从这个意义上说，评估自发姐妹染色单体交换（SCE）频率是评估基因组稳定性的有力工具。在这里，我们采用G显带、荧光加吉姆萨（FPG）和染色体定向荧光原位杂交（CO-FISH）方法来表征全基因组自发发生的SCE（G-SCE）的染色体特异性频率和端粒特异性SCE（T-SCE）。我们分析了两种圈养雄性物种的原代成纤维细胞培养物：（APA）和（ACH）。在这两个物种中均观察到高频率的G-SCE。有趣的是，G-SCE聚集在进化相关的染色体对上：ACH的染色体1、2、3、4和7，以及APA的染色体1、2、3、4/12、7和10。此外，还检测到观察到的和预期的G-SCE频率之间存在统计学上的显著差异，且与染色体大小无关。CO-FISH分析揭示了这两个物种中均存在端粒特异性重组事件，其中包括T-SCE，以及间质端粒信号和端粒重复，与ACH相比，APA染色体显示出更高的频率。我们的分析支持这样的假设，即易发生重组事件的染色体区域是脆弱位点和进化热点。因此，我们提出SCE分析作为非人类灵长类动物基因组不稳定的有价值指标。
