Collaborative: Mammalian Phylogeography in Regional Warm Deserts of North America

9629840哈夫纳最近在北美西南部出现了大片的艾瑞德兰，这使得许多人认为适应这些地区的动植物之间的关系模式也是最近才出现的。然而，许多物种都是古老的，在零星干燥的地方生存了数百万年。在合作研究中，大卫·J·哈夫纳和布雷特·R·里德尔将与他们的合作者一起，调查区域沙漠之间古代结构的可能性，并重建这些沙漠的分化序列。他们将通过线粒体DNA的序列差异来研究四类啮齿动物之间的遗传关系。这些啮齿动物目前仅限于地区性温暖的沙漠和邻近的查帕尔或荆棘灌木丛栖息地，并有化石记录表明，在550万年前的地区性沙漠早期发展期间，它们曾出现在研究区域。这些啮齿动物之间的关系将成为沙漠中其他动植物之间关系的指示器。Hafneros博士合作的一部分将涉及收集和识别啮齿动物群体，其中包括白脚和口袋鼠、羚羊松鼠和袋鼠，这些啮齿动物的目标是检测它们的线粒体DNA。考察队将前往美国西南部和墨西哥北部奇瓦瓦、大盆地、圣华金、索诺兰和半岛沙漠的33个地点，以及邻近的加利福尼亚州夏帕拉尔和西那罗亚荆棘灌木区，以及下加利福尼亚州附近的6个岛屿。这些岛屿样本预计将提供大约5000年前下加利福尼亚半岛大陆啮齿动物地理分布的估计，当时这些岛屿与半岛分离。参与者包括里德尔博士和墨西哥国立自治大学和南下加利福尼亚生物调查中心的同事。这项研究有望帮助人类了解物种以及物种的分布如何随着时间的推移而变化，特别是物种的这种变化可能如何受到物种所在地区的拓扑和气候变化的影响。

9629840 HAFNER The recent appearance of extensive regions of aridlands in southwestern North America has led many to assume that pattersn of relationships among the plants and animals adapted to these regions are also recent. Yet many of the species are ancient, having persisted in scattered dry sites for many millions of years. In collaborative investigations, David J. Hafner and Brett R. Riddle, together with their collaborators, will investigate the possibility of ancient structure among the regional deserts and reconstruct the sequence of divergence of these deserts. They will examine, by means of sequence divergences in mitochondrial DNA, the genetic relationships among four groups of rodents. These rodents are currently restricted to regional warm deserts and neighboring chaparral or thornscrub habitats, and have fossil records that indicate their presence in the study area during the early development of the regional deserts, up to 5.5 million years ago. Relationships among these rodents will serve as indicators of relationships among other animals and plants in the deserts. Dr. HafnerOs portion of the collaboration will involve collection and identification of the groups of rodents, which include white-footed and pocket mice, antelope ground squirrels, and kangaroo rats, targeted for examination of their mitochondrial DNA. Expeditions will be made to up to 33 sites in the Chihuahuan, Great Basin, San Joaquin, Sonoran, and Peninsular deserts of the southwestern United States and northern Mexico, as well as the neighboring California chaparral and Sinaloan thornscrub regions, and six islands off Baja California. The island samples are expected to provide estimates of the geographic distribution of the rodents on the Baja California peninsular mainland ca. 5,000 years ago, when the islands were separated from the peninsula. Participants include Dr. Riddle and colleagues at the Universidad Nacional Autonoma de Mexico and the Centro de Investigaciones Biologicas de Baja Californi a Sur. The research is expected to contribute to human understanding of how species, and the distribution of species, change over time, and especially how such changes in species may be influenced by changes in the topology and climate of the regions in which the species live.