Publication Date

2015-11-13

Availability

Embargoed

Embargo Period

2017-11-12

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology (Arts and Sciences)

Date of Defense

2015-07-16

First Committee Member

J. Albert C. Uy

Second Committee Member

William A. Searcy

Third Committee Member

Leonel Sternberg

Fourth Committee Member

Jaime A. Chaves

Abstract

Studies of divergence and speciation patterns in island systems have played an important role in the development and establishment of the allopatric speciation model. However, recent empirical support for divergence and speciation with gene flow means the importance of isolation for divergence in island systems needs to be re-examined. Here I explore the roles of geographic isolation and gene flow in the early stages of divergence of evolutionarily independent replicate populations of the Rufous Fantail Rhipidura rufifrons on satellite islands in southeastern Solomon Islands. These populations differ in the extent of morphological divergence from the main island, providing a unique opportunity to test between modes of divergence in an island system. Patterns of population structure, gene flow, and the evolutionary history of the system were determined from one mtDNA and five nuclear genetic markers. Two demographic factors, gene flow and divergence time, are closely associated with neutral genetic divergence and may explain the pattern of morphological divergence across the system. Additionally, extensive morphological divergence in this system is only occurring between islands experiencing little gene flow, providing support for the prevalence of allopatric divergence in island systems.

Keywords

allopatric speciation; gene flow; geographic isolation; Rhipidura rufifrons; island system

Available for download on Sunday, November 12, 2017

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