Eno Celeste C, Böttger Stefanie A, Walker Charles W
Molecular, Cellular and Biomedical Sciences, University of New Hampshire, 46 College Road, Durham, New Hampshire 03824, USA.
Biol Bull. 2009 Dec;217(3):306-12. doi: 10.1086/BBLv217n3p306.
The purple sea urchin, Strongylocentrotus purpuratus, is the only non-chordate deuterostome model with a fully sequenced genome. Chromosomal localization of individual genes and resulting gene maps are unavailable for this or for any sea urchin. As a result, the purple sea urchin genome has not been mapped onto specific chromosomes and remains inaccessible to genome-wide approaches addressing questions that require positional information for particular genes. Here we describe the first successful methods for karyotyping and localizing specific gene loci on chromosomes of Strongylocentrotus purpuratus and those of the phylogenetically related Strongylocentrotus droebachiensis. Both species have 42 chromosomes in their diploid genomes (n = 21). There are 2 large, 8 medium, and 10 small pairs, plus one putative sex pair. In both species, bindin genes were localized to 2 pair of homologous chromosomes by fluorescent in situ hybridization. Fluorescently labeled bacterial artificial chromosome clones generated from S. purpuratus for the functionally related genes brachyury, foxa, and foxb were localized to different chromosomes. Our protocols provide previously unavailable tools for developing a gene map for the purple sea urchin genome.
紫海胆（Strongylocentrotus purpuratus）是唯一一种基因组已完全测序的非脊索动物后口动物模型。目前，对于该物种或任何海胆而言，单个基因的染色体定位及由此产生的基因图谱均不可得。因此，紫海胆基因组尚未定位到特定染色体上，并且对于那些需要特定基因位置信息来解决问题的全基因组方法来说，该基因组仍然难以获取。在此，我们描述了在紫海胆及其系统发育相关物种——大西洋海胆（Strongylocentrotus droebachiensis）的染色体上进行核型分析和定位特定基因座的首个成功方法。这两个物种的二倍体基因组均有42条染色体（n = 21）。其中有2对大染色体、8对中染色体和10对小染色体，外加一对假定的性染色体对。在这两个物种中，通过荧光原位杂交将结合蛋白基因定位到了2对同源染色体上。从紫海胆中产生的用于功能相关基因短尾相关转录因子（brachyury）、叉头框蛋白A（foxa）和叉头框蛋白B（foxb）的荧光标记细菌人工染色体克隆被定位到了不同的染色体上。我们的实验方案为构建紫海胆基因组的基因图谱提供了此前无法获得的工具。
