CYTOGENETIC RELATIONSHIPS OF KEY DIPLOID MEMBERS OF THE MIMULUS GLABRATUS COMPLEX (SCROPHULARIACEAE)
CYTOGENETIC RELATIONSHIPS OF KEY DIPLOID MEMBERS OF THE MIMULUS GLABRATUS COMPLEX (SCROPHULARIACEAE)
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光滑芒草复合体（玄参科）关键二倍体成员的细胞遗传学关系
DOI：
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发表时间：
1970
期刊：
影响因子：
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通讯作者：
R. K. Vickery
中科院分区：
文献类型：
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作者：
W. Tai;R. K. Vickery
近缘物种和变种的光肩星天牛复合体表现出不同寻常的多倍体系列--不同寻常的是，在几乎整个西半球的长度上，多倍体水平从北到南逐渐增加。从加拿大南部到墨西哥东北部，从加利福尼亚州东部到大平原，都发现了分散的二倍体种群。相对罕见的四倍体出现在二倍体分布的南部界限上，从加利福尼亚州南部到墨西哥东北部。非整倍体-四倍体从墨西哥北部到危地马拉南部都有，但只在墨西哥中部的高地很常见。从哥伦比亚高地的安第斯山脉到巴塔哥尼亚南部的平原和山脉，南美洲大部分地区都偶尔发现六倍体种群(Vickery，1966,1969)。这种分布格局表明，光肩星天牛复合体在至少四次连续的适应性辐射中从北美向南扩散到南美洲的顶端--首先是二倍体，其次是四倍体，然后是非整倍体-四倍体，最后是六倍体。这些适应性辐射中的每一种似乎都是由一个或多个突变启动的，这些突变改变了复合体中该成员的染色体数量和气候耐受性、竞争能力或其他属性，使其能够扩散到新的区域。所有不同的突变，无论是多倍体还是非整倍体，似乎都直接或间接地涉及二倍体形式。因此，对二倍体形式的彻底细胞遗传学理解应该有助于洞察四倍体和六倍体产生的途径。因此，这项研究是为了研究关键的二倍体形式的细胞学和杂交行为，从而为我们阐明整个光肩星天牛复合体的进化关系的长期目标提供一些必要的基本信息。
The Mimulus glabratus complex of related species and varieties exhibits an unusual polyploid series-unusual in that the polyploid levels increase from north to south throughout almost the entire length of the Western Hemisphere. Scattered populations of the diploid forms are found from southern Canada to northeastern Mexico and from eastern California to the Great Plains. The relatively rare tetraploids occur along the southern limit of the distribution of the diploids from southern California to northeastern Mexico. The aneuploid-tetraploids range from northern Mexico to southern Guatemala but are common only in the highlands of central Mexico. Occasional populations of the hexaploid forms are found throughout much of South America from high in the Andes of Columbia to the plains and mountains of southern Patagonia (Vickery, 1966, 1969). This pattern of distribution suggests that the M. glabratus complex spread southward from North America almost to the tip of South America in at least four successive adaptive radiations-first the diploids, next the tetraploids, then the aneuploid-tetraploids, and finally the hexaploids. Each of these adaptive radiations appears to have been initiated by one or more mutations that changed the chromosome number and the climatic tolerance, competitive ability, or other attributes of that member of the complex which allowed it to spread into new areas. All of the various mutations, whether polyploid or aneuploid, appear to involve the diploid forms either directly or indirectly. Therefore, a thorough cytogenetic understanding of the diploid forms ought to provide insight into the pathways by which the tetraploids and hexaploids arose. So, this study was initiated to investigate the cytology and crossing behavior of key diploid forms and thus provide some of the basic information needed for our long-range goal of elucidating the evolutionary relationship of the entire M. glabratus complex.