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Full-Text Articles in Life Sciences
An Evolving Epigenome That Determines Tissue And Cell Specificity, Renee Louise Sears
An Evolving Epigenome That Determines Tissue And Cell Specificity, Renee Louise Sears
Arts & Sciences Electronic Theses and Dissertations
Understanding the mechanisms driving phenotypic variation is a major goal of biology that unifies classical genetics with the emerging fields of genomics and epigenomics. Human and mouse share over 90% of genes and global tissue-specific patterns of expression are maintained between the species. Thus, it is hypothesized that gene expression is influenced through distinctive regulation among species in order to account for the unmistakable phenotypic divergence. DNA methylation, histone modifications, open chromatin patterns, transcription factor binding, and other epigenetic factors are all associated with shaping, maintaining, and repressing regulatory regions which in turn coordinate gene expression. It is vital to …
Aging Of The Reproductive System And Of Germline Stem Cells In Caenorhabditis, Zuzana Kocsisova
Aging Of The Reproductive System And Of Germline Stem Cells In Caenorhabditis, Zuzana Kocsisova
Arts & Sciences Electronic Theses and Dissertations
C. elegans hermaphrodites display dramatic age-related decline of reproduction early in life while somatic functions are still robust. To understand why the germline fails so early, we analyzed the assembly line of oocyte production that generates fertilized eggs in mated hermaphrodites with sufficient sperm. Aging germlines displayed both sporadic and population-wide changes. A small fraction of aging animals displayed endomitotic oocytes in the germline and other defects. By contrast, all animals displayed age-related decreases in germline size and function. As early as day 3 of adulthood, animals displayed fewer stem cells and a slower cell cycle, which combine to substantially …
Cyanogenesis And The Genetics Of Local Adaptation In White Clover (Trifolium Repens L.), Sara Jeanes Wright
Cyanogenesis And The Genetics Of Local Adaptation In White Clover (Trifolium Repens L.), Sara Jeanes Wright
Arts & Sciences Electronic Theses and Dissertations
Geographically widespread species experience varied selection across their ranges, and adaptation to local environments plays a critical role in their ability to persist. Understanding the genetic basis of local adaptation is a longstanding goal in evolutionary biology and provides practical information for agriculture and conservation. However, the genetic architecture of local adaptation has been characterized in relatively few plant species, primarily those with short lifespans and high rates of self-fertilization. Moreover, for plants, chemical defenses are known to play an important role in adaptation, but the extent to which they contribute to local adaptation is less understood. This dissertation provides …