Evolutionary consequences of experimental transfer into yeast populations of an animal transposon

动物转座子实验转移到酵母群体中的进化后果

• 批准号: 1655999
• 负责人: Clifford Zeyl
• 金额: $ 10.79万
• 依托单位: Wake Forest University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-03-15 至 2022-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1655999&HistoricalAwards=false
• 关键词: Evolutionary; consequences; experimental; transfer; into

This project will investigate a major process of evolutionary change, the rearrangement of genomes by transposable genetic elements. Plant, animal and fungal genome sizes vary widely. For instance, the lungfish genome is 10,000 times as large as a yeast genome. In some plants, genomes are even larger. This tremendous variation in the amount of DNA is not just related to the complexity or the size of the organism. It results mostly from variation in the abundance of short DNA sequences that spread copies of themselves among the chromosomes of their host. Known as transposable elements, these "jumping genes" can multiply within a genome until they make up most of an organism's DNA. Knowing how this occurs will allow us to understand why there is such great variation in genome size. Jumping genes are also important because they cause mutations when they jump. Because these DNA sequences can spread and diversify by exploiting rather than benefitting the organism that carries them, jumping genes require us to think beyond the function of a given gene in trying to understand the genome. This project will allow observation of a jumping gene's spread directly, as it occurs, in the genome of baker's yeast. Broader impacts of the proposed work include the training of graduate and undergraduate students in evolutionary genomics. The transposable element that will be used as an experimental invader is Hermes. It is a transposable element isolated from the housefly. It has an entirely different structure and mechanism of transposition from any of the transposable elements found in the yeast genome. This Hermes transposable element has been modified for high transposition rates in yeast under the control of a galactose genetic promoter. Once Hermes is introduced to the yeast, hundreds of yeast lineages will be evolved for hundreds of generations. Selective gene sequencing of areas surrounding the transposable elements will be used to track proliferation or movement of Hermes over time. Hypotheses will be tested concerning three questions. First, what enables a foreign transposable element to invade a new population? Second, what are the effects of a newly established transposable element on the ability of that population to respond to new selective pressures? The final question is, how quickly do new mechanisms to suppress an alien transposon evolve in a host population under strong selection from a transposable element with very high transposition rates?

这个项目将研究进化变化的一个主要过程，即转座遗传因子对基因组的重排。 植物、动物和真菌的基因组大小差别很大。例如，肺鱼的基因组是酵母基因组的10,000倍。有些植物的基因组甚至更大。DNA数量的巨大变化不仅仅与生物体的复杂性或大小有关。 它主要是由于短DNA序列丰度的变化，这些短DNA序列在宿主的染色体中传播自身的拷贝。 被称为转座因子的这些“跳跃基因”可以在基因组内繁殖，直到它们构成生物体的大部分DNA。了解这是如何发生的将使我们能够理解为什么基因组大小会有如此大的变化。跳跃基因也很重要，因为它们在跳跃时会引起突变。因为这些DNA序列可以通过利用而不是受益于携带它们的生物体来传播和多样化，跳跃基因要求我们在试图理解基因组时超越给定基因的功能。这个项目将允许观察跳跃基因的直接传播，因为它发生在面包酵母的基因组中。拟议工作的更广泛影响包括对研究生和本科生进行进化基因组学培训。将被用作实验入侵者的转座因子是爱马仕。它是一种从家蝇中分离出来的转座因子。它具有与酵母基因组中发现的任何转座因子完全不同的结构和转座机制。 该爱马仕转座因子已被修饰，在半乳糖遗传启动子的控制下在酵母中具有高转座率。一旦爱马仕被引入酵母，数百种酵母谱系将进化数百代。转座因子周围区域的选择性基因测序将用于跟踪爱马仕随时间的增殖或运动。将对三个问题进行假设检验。首先，是什么使外来转座因子能够入侵新种群？第二，新建立的转座因子对该种群应对新的选择压力的能力有什么影响？最后一个问题是，在转座率非常高的转座因子的强选择下，抑制外来转座子的新机制在宿主种群中进化的速度有多快？