Collaborative Research: Life History Variation in Copepods: Modulation through Chromatin Diminution and Endoreduplication

合作研究：桡足类生活史变异：通过染色质减少和内复制进行调节

• 批准号: 0080921
• 负责人: Ellen Rasch
• 金额: $ 9万
• 依托单位: East Tennessee State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-09-15 至 2004-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0080921&HistoricalAwards=false
• 关键词: Collaborative; Research; Life; History; Variation

0080921Rasch This research investigates responses of aquatic microcrustaceans to massive losses, gains, and reorganizations of genomic DNA. The focus is on embryonic chromatin diminution - reduction in size and reorganization of the genome, with additional exploratory research on endoreduplication - the amplification of nuclear DNA without subsequent mitosis. The PI's will investigate whether variation in DNA content in somatic and germ cell lineages can explain variation in developmental time and embryonic and adult body sizes through effects on bulk size of the genome. Research will include reconstruction of a phylogeny of the Cyclopidae and use of phylogenetically-independent contrasts to test for correlated evolution of adult somatic DNA content with developmental rate and adult body size. The PIs will investigate whether large amounts of germline DNA in embryos make possible higher rates of protein transcription at times during development when there is greatest need for such transcripts. Quantitative changes in DNA will be measured using cytophotometry and isotopically labeled DNA and RNA precursors. Copepods are ideal for examining evolution of large-scale changes in the genome because their genome size varies greatly among species, mechanisms that modulate their DNA contents are known, their life history variation and population biology are well studied, and their chromosomes are amenable to quantitative and comparative analyses. Copepods may be the most abundant multicellular organisms in the oceans, are a primary diet item of many fish, and thus play a major role in global ecology.

0080921Rasch 这项研究调查了水生微型甲壳类动物对基因组 DNA 大量丢失、增加和重组的反应。 重点是胚胎染色质的减少——基因组大小的减小和重组，以及核内复制的额外探索性研究——核DNA的扩增，而没有随后的有丝分裂。 PI 将研究体细胞和生殖细胞谱系中 DNA 含量的变化是否可以通过对基因组体积大小的影响来解释发育时间以及胚胎和成人体型大小的变化。 研究将包括重建独眼龙科的系统发育，并使用独立于系统发育的对比来测试成体体细胞 DNA 含量与发育速率和成体体型的相关进化。 PI 将调查胚胎中大量种系 DNA 是否可能在发育过程中最需要此类转录物的时候提高蛋白质转录率。 DNA 的定量变化将使用细胞光度法和同位素标记的 DNA 和 RNA 前体进行测量。 桡足类动物是研究基因组大规模变化进化的理想选择，因为它们的基因组大小在物种之间差异很大，调节其 DNA 含量的机制是已知的，它们的生活史变异和种群生物学得到了充分研究，并且它们的染色体适合定量和比较分析。 桡足类可能是海洋中最丰富的多细胞生物，是许多鱼类的主要食物，因此在全球生态中发挥着重要作用。