棘头梅童鱼中期染色体物理长度的估测

棘头梅童鱼（Collichthys lucidus）是我国重要的海洋经济鱼类之一，具有特别的多性染色体系统（X1X1X2X2/X1X2Y)。本研究使用流式细胞术（flow cytometry，FCM）首次估测了棘头梅童鱼基因组的大小，并利用碘化丙啶染色与图像分析软件测定棘头梅童鱼24对染色体的相对面积、相对长度以及相对累积荧光强度，估算了染色体的物理长度。结果显示，雌性和雄性棘头梅童鱼的基因组大小分别为802.91 ± 2.19 Mb和786.52 ± 1.95 Mb。雌性基因组显著大于雄性基因组（约16.39 Mb）。雌性的核型公式为2n = 48 = 48t，臂数NF = 48， 染色体估测物理长度在（22.17 ± 0.72） Mb ~ （46.30 ± 1.06） Mb之间。雄性的核型公式为2n = 47 = 1m + 46t，臂数NF = 48。其中，雄性特有的m染色体为Y染色体，其估测物理长度为（62.95 ± 2.89 ）Mb。染色体的估测物理长度与相对面积、相对长度均成正线性相关。研究结果为棘头梅童鱼染色体的识别、配对提供更丰富的信息，为棘头梅童鱼Y染色体的组装及石首鱼科鱼类染色体进化提供参考数据。

Physical length of metaphase chromosomes in Collichthys lucidus

Spinyhead croaker (Collichthys lucidus) is one of the important marine economy species in China, and being of a special multiple sex chromosome system X1X1X2X2/X1X2Y. In the present study, the genome size of C. lucidus was determined by using flow cytometry, and the relative length, the relative area and the integrated optical density (IOD) of 24pairs of chromosomes were determined using PI staining and microscopic image analysis software, and the physical length of chromosomes was estimated based on the values of IOD. The results showed that male and female''s genome size were respectively estimated as (786.52 ± 1.95) Mb and (802.91 ± 2.19) Mb. Female genome significantly larger than male genome (about 16.39 Mb). The genome of female comprised 24 pairs of telocentric chromosomes, the karyotype formula is 2n = 48 = 48t, NF = 48, with the physical length ranging from (22.17 ± 0.72) Mb to (46.30 ± 1.06) Mb. The genome of male comprised 46 telocentric chromosomes and one metacentric chromosome, the karyotype formula is 2n = 47 = 46t + 1m, NF = 48. The male-specific metacentric chromosome was Y chromosome, with an estimated physical length of (62.95 ± 2.89) Mb. Physical lengths of chromosomes are correlated linearly with the relative area and the relative lengths. Above all, new parameters of chromosomes present in this paper will facilitate to chromosome identification and pairing of C. lucidus, which will serve as reference data for the assembly of the Y chromosome and the evolution of chromosome in Sciaenidae.