摘要
在各类脊椎动物中，软骨鱼类是开展染色体研究最少的类群。迄今为止，文献共报道了70种软骨鱼的核型，仅占现生838种软骨鱼类的8．35％，包括31种鲨类，37种鳐类和2种全头类。已报道的软骨鱼类二倍体染色体数为52～104（巴西双鳍电鳐二倍体染色体数为28例外），常存在微染色体。在不同的分类阶元，相对原始的软骨鱼类具有较多的染色体数，端部和亚端部着丝粒染色体较多，多有微染色体。软骨鱼类染色体进化趋势表现为个体染色体数目的减少。中部和亚中部着丝粒染色体数目的增多，并伴随微染色体的消失。软骨鱼类是核DNA含量较大的脊椎动物。已报道144种软骨鱼类的核DNA含量，其变化较大，为3．0～34．1pg／N，全头类的核DNA含量最小，角鲨目和扁鲨目的核DNA含量最大。近年来，在软骨鱼类染色体的C带、核仁组织区（NOR）染色、限制性内切酶显带、特异DNA探针如端粒序列和短散布重复序列（SINE序列）的荧光原位杂交等方面取得了较大进展。现代分子生物学技术也被用于一些软骨鱼类的基因组研究，在重复DNA序列、随体DNA家族和微卫星位点等方面均取得一些成果。
The chromosome of Chondrichthyes is the least investigated among vertebrates. The karyotypes of 70 out of 838 known species（8.35 % ） have been described, including 31 Selachomorpha, 37 Batomorpha and 2 Holocephalian species. The diploid chromosome number ranges from 52 to 104, with the exception of Narcine brasiliensis which is 28, and microchromosomes are often present. The most primitive species in the different taxa have high diploid chromosome numbers, with many telocentric and acrocentric elements, and most of then have microchromosomes. The general trend in all groups seems to be a progressive increase of the metacentric and submetacentric chromosome number in the most specialized species, which is followed by the loss of the microchromosomes. Chondrichthyes have the larger genome sizes among vertebrates. Nu- clear DNA contents of 144 chondrichthian species have been described. In the whole class, the species examined vary greatly in genome size, from 3.0 to 34.1 pg/N, the lowest values have been observed in holocephalans, while the highest values in Squaliformes and Squatiniformes. In recent years, studies on chondrichthian chromosome have been improved by C-banding, nucleolar organizer regions（NOR） staining, restriction enzymes in situ digestion and fluorescent in situ hybridization（FISH） with specific DNA probes, such as telomeric sequence and short interspersed repetitive elements（SINE） sequences. The genomes of several chondrichthian fish have also been studied by up-to-date molecular techniques, especially as regards the repetitive DNA sequences, satellite DNA family and microsatellite loci.
出处
《中国水产科学》
CAS
CSCD
北大核心
2006年第5期856-866,共11页
Journal of Fishery Sciences of China
基金
福建省教育厅科技项目(JA03136)
