Am J Bot. 1997 Oct;84(10):1372.
Two of the four members of subsection Contortae of the genus Pinus occur in the southeastern United States: Pinus virginiana, which ranges throughout the southern and central Appalachian Mountains, and P. clausa, which is restricted to Florida and southern Alabama. We examined allozyme variation within P. virginiana and genetic relationships between this species and the two varieties of P. clausa (var. clausa and var. immuginata). P. virginiana maintains more genetic diversity at both the species (Hes = 0.139) and population (Hep = 0.128) levels than the other three species in the subsection, which may reflect the combination of its widespread distribution and the absence of cone serotiny. Genetic differentiation among populations in P. virginiana was relatively low (GST = 0.053), but significant contrasts in allozyme frequencies and genetic diversity were apparent between populations to the northwest vs. outheast of the Appalachian Mountains. These regional differences likely resulted initially from historical processes that occurred during the Pleistocene and early Holocene, and have been reinforced by modern selective pressures and barriers to gene flow. The mean genetic distance between populations of P. virginiana and P. clausa (D = 0.071) was greater than that between populations of the two varieties of P. clausa (D = 0.012), which suggests that the two varieties diverged at some point after the separation of the two species.
分布于阿巴拉契亚山脉南部和中部的弗吉尼亚松，以及仅限于佛罗里达州和阿拉巴马州南部的闭锁松。我们研究了弗吉尼亚松内的等位酶变异以及该物种与闭锁松的两个变种（闭锁变种和immuginata 变种）之间的遗传关系。弗吉尼亚松在物种（Hes = 0.139）和种群（Hep = 0.128）水平上都保持着比亚属其他三个物种更高的遗传多样性，这可能反映了其广泛分布和无球果结实的结合。弗吉尼亚松种群间的遗传分化相对较低（GST = 0.053），但在阿巴拉契亚山脉西北和东南的种群间，等位酶频率和遗传多样性存在明显差异。这些区域差异最初可能是由于更新世和全新世早期发生的历史过程造成的，并且受到现代选择压力和基因流障碍的加强。弗吉尼亚松和闭锁松种群之间的平均遗传距离（D = 0.071）大于闭锁松两个变种（D = 0.012）之间的遗传距离，这表明两个变种在两个物种分离后某个时间点发生了分化。
