Show simple item record

dc.contributor.authorCrawford, Nicholas Geoffreyen_US
dc.date.accessioned2016-04-11T15:44:48Z
dc.date.available2016-04-11T15:44:48Z
dc.date.issued2013
dc.identifier.urihttps://hdl.handle.net/2144/15658
dc.description.abstractRecent advances in high-throughput, genomic sequencing allow unprecedented insight into the evolution of biodiversity. Chapter 1 of this thesis is a phylogenetic study of 1,145 sequenced loci, isolated using a novel high-throughput sequence capture methodology to address the phylogenetic position of turtles within tetrapods. The results reported here unambiguously place turtles as sister to archosaurs and resolve this long-standing question. Chapter 2 investigates the genetic basis of colorful pigmentation in the Green anole (Anolis carolinensis) by sequencing complete transcriptomes from the green dorsal, white ventral and pink dewlap skin. Anoles comprise an adaptive radiation of more than 400 species and color plays a central role in their ecology and evolution, but little is known about the genetic basis of colorful pigmentation in any vertebrate. This study identified 1,719 differentially expressed genes among the three differently colored tissues. Twenty-three of these genes are involved in melanin, pteridine, and carotenoid pigmentation pathways that contribute to the coloration of anole skin. Identifying candidate genes for colorful pigmentation is a significant advance that opens the field for comparative analysis in other taxa. To determine if the genes identified in Chapter 2 are involved in population divergence and speciation, Chapter 3 investigates the complete genomes of twenty individuals from two closely related subspecies of Anolis marmoratus. While the two subspecies differ markedly in pigmentation, this study found few genetic differences between populations except in five regions of the genome, which together contained 447 genes. Of these genes, only two, melanophilin (mlph) and 'cluster of differentiation 36' (cd36), are associated with pigmentation. The intersection of the genes identified in Chapter 2 and Chapter 3 includes both cd36 and mlph, suggesting that both are involved in divergence of coloration. Cd36 is of particular interest because it regulates the uptake of carotenoid pigments and is an important candidate gene contributing to carotenoid pigmentation. Together, this research demonstrates the power of genomic approaches to address fundamental questions in systematics, micro-evolution, and speciation. The findings bolster the emerging field of phylogenomics and broadly impact future research into the genetic basis of coloration in vertebrates.en_US
dc.language.isoen_US
dc.subjectEvolution & developmenten_US
dc.subjectAnolisen_US
dc.subjectGuadeloupeen_US
dc.subjectGWASen_US
dc.subjectPigmenationen_US
dc.subjectTurtleen_US
dc.subjectUCEen_US
dc.titleGenomic analysis of macro- and micro-evolution in the reptiliaen_US
dc.typeThesis/Dissertationen_US
dc.date.updated2016-04-08T20:05:36Z
etd.degree.nameDoctor of Philosophyen_US
etd.degree.leveldoctoralen_US
etd.degree.disciplineBiologyen_US
etd.degree.grantorBoston Universityen_US


This item appears in the following Collection(s)

Show simple item record