斑点叉尾鮰全基因组微卫星分布特征分析

为了解斑点叉尾鮰(Ictalurus punctatus)全基因组中完整型微卫星的分布特征，本研究使用生物信息学软件MISA对其全基因组微卫星进行了搜索并分析。结果显示，在斑点叉尾鮰29条染色体中，筛选到完整型微卫星共510 256个，总长度达11 036 941 bp。其中，微卫星数量最多的是2号染色体(25 284个)，其次分别是3号、1号和5号染色体，29号染色体的微卫星数量最少，只有11 591个。每条染色体长度与位于其上的微卫星的数量均显著相关(SPSS, r=0.98, P<0.01)。27号染色体的微卫星相对丰度最大(785.03个/Mb)，11号染色体的微卫星相对丰度最小(615.89个/Mb)。6种重复拷贝类型的微卫星中，单碱基的数量最多，占总数的45.31%，随后依次是二碱基(38.53%)、三碱基(8.73%)、四碱基(6.93%)、五碱基(0.46%)和六碱基(0.04%)。斑点叉尾鮰全基因组微卫星中，前10种优势重复拷贝类别为A、AC、AG、AT、AAT、AAAT、C、AAC、AAAC和AAG，表现出明显的A、T碱基优势。本研究结果可为进一步研究斑点叉尾鮰全基因组特征提供参考，并为今后进行斑点叉尾鮰分子标记辅助育种及遗传信息评估等工作提供基础资料。

Analysis of Microsatellite Distribution Characteristics in the Channel Catfish (Ictalurus punctatus) Genome

To understand the distribution of perfect microsatellites in the genome of the channel catfish (Ictalurus punctatus), we used MISA, a bioinformatics software package, to search and analyze the microsatellites. A total of 510 256 perfect microsatellites were isolated from 29 chromosomes of I. punctatus, with a total length of 11 036 941 bp. The chromosome containing the largest number of microsatellites was chromosome 2 (25 284), followed by chromosomes 3, 1, and 5. Chromosome 29 had the lowest number of microsatellites (11 591). The length of each chromosome was significantly correlated with the number of microsatellites it contained (SPSS, r = 0.98, P < 0.01). The highest relative abundance of microsatellites was found on chromosome 27 (785.03 ind./Mb), and the lowest was on chromosome 11 (615.89 ind./Mb). Among the six repeat types, mononucleotides were the most frequent, accounting for 45.31% of the total, followed by dinucleotides (38.53%), trinucleotides (8.73%), tetranucleotides (6.93%), pentanucleotides (0.46%), and hexanucleotides (0.04%). The predominantly repeated microsatellite sequences in the I. punctatus genome were A, AC, AG, AT, AAT, AAAT, C, AAC, AAAC, and AAG, showing an obvious inclination towards A and T bases. The results of this study provide a reference for the further study of I. punctatus genome characteristics and contribute basic data for future investigations into molecular marker-assisted breeding and genetic information assessment of I. punctatus.