Advanced search options

Advanced Search Options 🞨

Browse by author name (“Author name starts with…”).

Find ETDs with:

in
/  
in
/  
in
/  
in

Written in Published in Earliest date Latest date

Sorted by

Results per page:

Sorted by: relevance · author · university · dateNew search

You searched for +publisher:"Cornell University" +contributor:("Reed, Robert D."). Showing records 1 – 3 of 3 total matches.

Search Limiters

Last 2 Years | English Only

No search limiters apply to these results.

▼ Search Limiters


Cornell University

1. Lewis, James Joseph. CIS-REGULATORY EVOLUTION IN HELICONIUS BUTTERFLIES.

Degree: PhD, Ecology and Evolutionary Biology, 2017, Cornell University

cis-Regulatory element evolution is a key mechanism of biological diversification. Surprisingly little is known, however, about patterns of gene regulatory evolution across a range of divergence times, and the extent to which such variation drives local genomic adaptation. In chapter 1, we introduce the functional genomic methods used in this dissertation, and briefly discuss the current state and future prospects for the study of gene regulatory evolution. In chapter 2, we characterize the evolution of regulatory loci in butterflies and moths using ChIP-seq annotation of regulatory elements across three stages of Heliconius head development. In the process we provide a high quality, functionally annotated genome assembly for the butterfly Heliconius erato. Comparing cis-regulatory element conservation across six lepidopteran genomes, we find that regulatory sequences evolve at a pace similar to that of protein-coding regions. we also observe that elements active at multiple developmental stages are markedly more conserved than elements with stage-specific activity. Surprisingly, we also find that stage-specific proximal and distal regulatory elements evolve at nearly identical rates. This study provides a benchmark for genome-wide patterns of regulatory element evolution in insects, and shows that developmental timing of activity strongly predicts patterns of regulatory sequence evolution. In chapter 3, we use functional assays for chromatin accessibility and histone modifications to test the hypothesis that intraspecific genomic divergence is linked to regulatory variation between distinct populations of Heliconius butterflies. We show that population-level variability in both chromatin accessibility and regulatory activity are abundant within the Heliconius genome. We further show that differences in regulatory activity between populations do not require associated differences in chromatin accessibility, illustrating that different modes of regulatory variation can be evolutionarily decoupled. Importantly, patterns of regulatory variation depart from neutral expectations, suggesting that selection underlies much of the observed regulatory divergence. Supporting this, genomic regions with high Fst are highly enriched for variable regulatory elements, and half of all differentially expressed genes have variable promoter-associated regulatory elements. Our work shows that regulatory elements vary between populations at different functional levels, and that selection on variable elements is a major force underlying genomic divergence within species. Advisors/Committee Members: Reed, Robert D. (chair), Clark, Andrew (committee member), McCune, Amy R. (committee member).

Subjects/Keywords: Evolution & development; Biology

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Lewis, J. J. (2017). CIS-REGULATORY EVOLUTION IN HELICONIUS BUTTERFLIES. (Doctoral Dissertation). Cornell University. Retrieved from http://hdl.handle.net/1813/47802

Chicago Manual of Style (16th Edition):

Lewis, James Joseph. “CIS-REGULATORY EVOLUTION IN HELICONIUS BUTTERFLIES.” 2017. Doctoral Dissertation, Cornell University. Accessed October 30, 2020. http://hdl.handle.net/1813/47802.

MLA Handbook (7th Edition):

Lewis, James Joseph. “CIS-REGULATORY EVOLUTION IN HELICONIUS BUTTERFLIES.” 2017. Web. 30 Oct 2020.

Vancouver:

Lewis JJ. CIS-REGULATORY EVOLUTION IN HELICONIUS BUTTERFLIES. [Internet] [Doctoral dissertation]. Cornell University; 2017. [cited 2020 Oct 30]. Available from: http://hdl.handle.net/1813/47802.

Council of Science Editors:

Lewis JJ. CIS-REGULATORY EVOLUTION IN HELICONIUS BUTTERFLIES. [Doctoral Dissertation]. Cornell University; 2017. Available from: http://hdl.handle.net/1813/47802

2. Rondem, Kathleen. CHARACTERIZING THE OPTIX NETWORK IN HELICONIUS BUTTERFLY WING COLOR PATTERNING.

Degree: M.S., Ecology and Evolutionary Biology, Ecology and Evolutionary Biology, 2018, Cornell University

Heliconius butterflies are an incredibly diverse species, with many displaying bold red, black and yellow coloring. Interestingly, a single gene, optix, has been shown to be responsible for the red coloring of these as well as many other butterflies within the Lepidoptera order. Optix is a highly conserved transcription factor with ancestral function in Drosophila eye development, so how has this gene evolved its function in butterfly wing pigmentation? Here, I describe work I did to elucidate both the upstream and downstream actors of the Optix network in the Heliconius wing pigmentation pathway in an effort to provide insight into how this novel function of optix has evolved. First, I explore the role of optix regulatory elements in wing color patterning using the CRISPR/Cas9 system to delete candidate optix cis-regulatory elements. I then investigate the conservation of the ancestral Optix eye network in the pigmentation pathway by deleting candidate downstream target genes of Optix and describe the resulting wing pattern mutations. This work provides foundational information on the role of this network in Heliconius wing color patterning and how it may have evolved. Advisors/Committee Members: Reed, Robert D. (chair), Geber, Monica Ann (committee member), Wolfner, Mariana Federica (committee member).

Subjects/Keywords: Evolution & development; butterfly; gene network; heliconius; optix; wing patterning; evolution

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Rondem, K. (2018). CHARACTERIZING THE OPTIX NETWORK IN HELICONIUS BUTTERFLY WING COLOR PATTERNING. (Masters Thesis). Cornell University. Retrieved from http://hdl.handle.net/1813/59619

Chicago Manual of Style (16th Edition):

Rondem, Kathleen. “CHARACTERIZING THE OPTIX NETWORK IN HELICONIUS BUTTERFLY WING COLOR PATTERNING.” 2018. Masters Thesis, Cornell University. Accessed October 30, 2020. http://hdl.handle.net/1813/59619.

MLA Handbook (7th Edition):

Rondem, Kathleen. “CHARACTERIZING THE OPTIX NETWORK IN HELICONIUS BUTTERFLY WING COLOR PATTERNING.” 2018. Web. 30 Oct 2020.

Vancouver:

Rondem K. CHARACTERIZING THE OPTIX NETWORK IN HELICONIUS BUTTERFLY WING COLOR PATTERNING. [Internet] [Masters thesis]. Cornell University; 2018. [cited 2020 Oct 30]. Available from: http://hdl.handle.net/1813/59619.

Council of Science Editors:

Rondem K. CHARACTERIZING THE OPTIX NETWORK IN HELICONIUS BUTTERFLY WING COLOR PATTERNING. [Masters Thesis]. Cornell University; 2018. Available from: http://hdl.handle.net/1813/59619

3. Mason, Nicholas A. TEMPO, MODE, AND MECHANISMS OF PHENOTYPIC EVOLUTION AND SPECIATION IN BIRDS.

Degree: PhD, Ecology and Evolutionary Biology, 2017, Cornell University

Birds are remarkably diverse, both in terms of species richness and diversity in phenotypes. A longstanding goal in evolution and ecology is to document patterns of biodiversity and infer the biological processes that contribute to speciation and phenotypic evolution. Here, I take a multidimensional approach to examine the tempo, mode, and mechanisms of phenotypic evolution and speciation in birds. I first document a positive association between rates of vocal evolution and speciation in two large lineages in Neotropical birds. I then explore phenotypic and genetic variation in two lineages of songbirds: the White-collared Seedeater (Sporophila torqueola) and the Holarctic redpoll finches (Acanthis sp.). Finally, I quantify phenotypic change in Horned Lark of the Imperial Valley in southern California, where the desert has been transformed into agricultural land. Collectively, these studies provide different perspectives on avian biodiversity and together illustrate the immense value of natural history collections as repositories of phenotypic and genetic data. Advisors/Committee Members: Lovette, John I. (chair), Zamudio, Kelly (committee member), Reed, Robert D. (committee member), Searle, Jeremy B. (committee member), Danforth, Bryan N. (committee member).

Subjects/Keywords: Biology; evolution; Ecology; Biogeography; Ornithology; Systematics; Taxonomy

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Mason, N. A. (2017). TEMPO, MODE, AND MECHANISMS OF PHENOTYPIC EVOLUTION AND SPECIATION IN BIRDS. (Doctoral Dissertation). Cornell University. Retrieved from http://hdl.handle.net/1813/59095

Chicago Manual of Style (16th Edition):

Mason, Nicholas A. “TEMPO, MODE, AND MECHANISMS OF PHENOTYPIC EVOLUTION AND SPECIATION IN BIRDS.” 2017. Doctoral Dissertation, Cornell University. Accessed October 30, 2020. http://hdl.handle.net/1813/59095.

MLA Handbook (7th Edition):

Mason, Nicholas A. “TEMPO, MODE, AND MECHANISMS OF PHENOTYPIC EVOLUTION AND SPECIATION IN BIRDS.” 2017. Web. 30 Oct 2020.

Vancouver:

Mason NA. TEMPO, MODE, AND MECHANISMS OF PHENOTYPIC EVOLUTION AND SPECIATION IN BIRDS. [Internet] [Doctoral dissertation]. Cornell University; 2017. [cited 2020 Oct 30]. Available from: http://hdl.handle.net/1813/59095.

Council of Science Editors:

Mason NA. TEMPO, MODE, AND MECHANISMS OF PHENOTYPIC EVOLUTION AND SPECIATION IN BIRDS. [Doctoral Dissertation]. Cornell University; 2017. Available from: http://hdl.handle.net/1813/59095

.