Dissertation Research: Consequences of Hybridization in the Harvester Ant Pogonomyrmex

论文研究：收割蚁 Pogonomyrmex 杂交的后果

• 批准号: 0508892
• 负责人: Jennifer Fewell
• 金额: $ 1.08万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0508892&HistoricalAwards=false
• 关键词: Dissertation; Research; Consequences; Hybridization; Harvester

Like the mule, hybrids between species or lineages are often considered an evolutionary dead end. However, recent studies suggest that hybrids can be important in shaping evolution. While most hybrid gene mixtures are unsuccessful, some are beneficial and result in new strategies to cope with changing ecological and social environments. In Pogonomyrmex seed-harvester ants, hybridization has produced a unique social and reproductive structure, in which queens must mate with males of two different genetic lineages to produce both workers and daughter queens. Daughters of the queen and males of the same lineage develop into queens. Hybrid daughters between the queen and males of the alternate lineage become sterile workers. This system of genetic caste determination violates the widely held assumption that whether a female becomes a worker or queen has to be based on differences in nutrition or other environmental factors, and not genetics, because gene combinations producing sterility should be selected against. This system occurs within two closely related harvester ant species, P. rugosus and P. barbatus, leading to the hypothesis that it originally evolved as a result of incomplete hybridization between the two species that lead to the development of two interdependent genetic lineages. However, preliminary evidence suggests that this is not the case and that it may have evolved initially in one species (P. barbatus) then spread to the other. To test these hypotheses, the extent and consequences of hybridization within and between these species of seed-harvester ants will be examined using mitochondrial and nuclear genetic analyses. This work will contribute to our understanding of the role that hybridization plays in evolution, especially the evolution of social systems. This research will also provide opportunities for a graduate student and several undergraduates to learn molecular techniques and analyses with broad applications in evolutionary biology.

就像骡子一样，物种或血统之间的杂交通常被认为是进化的死胡同。然而，最近的研究表明，杂交在形成进化过程中可能很重要。虽然大多数杂交基因混合是不成功的，但有些是有益的，并产生了应对不断变化的生态和社会环境的新策略。在Pogonomyrmex种子收获蚁中，杂交产生了一种独特的社会和生殖结构，蚁后必须与两种不同遗传谱系的雄性交配，才能产生工蚁和蚁后。女王的女儿和同一血统的男性发展成为女王。雌蜂和雄蜂的杂交后代成为不育的工蜂。这种由基因决定等级的制度违背了人们普遍持有的假设，即女性是否成为工蜂或女王必须基于营养或其他环境因素的差异，而不是基于基因，因为产生不育的基因组合应该被选择反对。这一系统发生在两种密切相关的收获蚁物种中，即P. rugosus和P. barbatus，这导致了一种假设，即它最初是由于两种物种之间的不完全杂交而进化而来的，这种杂交导致了两种相互依赖的遗传谱系的发展。然而，初步证据表明，情况并非如此，它可能最初在一个物种（P. barbatus）中进化，然后传播到另一个物种。为了验证这些假设，将使用线粒体和核遗传分析来检查这些种子收获蚁物种内部和之间杂交的程度和后果。这项工作将有助于我们理解杂交在进化中所起的作用，特别是社会系统的进化。这项研究也将为一名研究生和几名本科生提供机会，学习分子技术和分析在进化生物学中的广泛应用。