자료유형  

 학위논문

Control Number  

0016934588

International Standard Book Number  

9798380316163

Dewey Decimal Classification Number  

333

Main Entry-Personal Name  

Nguyen, Tram.

Publication, Distribution, etc. (Imprint  

[S.l.] : Cornell University., 2023

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2023

Physical Description  

1 online resource(176 p.)

General Note  

Source: Dissertations Abstracts International, Volume: 85-03, Section: B.

General Note  

Advisor: Clark, Andrew.

Dissertation Note  

Thesis (Ph.D.)--Cornell University, 2023.

Restrictions on Access Note  

This item must not be sold to any third party vendors.

Summary, Etc.  

요약Understanding the genomic consequences of population decline is a dynamic challenge in evolutionary biology and conservation. Declining population sizes can lead to reduced heterozygosity and elevated frequency of deleterious alleles, resulting in inbreeding depression, increased susceptibility to diseases, and reduced adaptive capacity. However, empirical research, especially in populations with ongoing gene flow, remains scarce. To investigate these dynamics, I integrate ecological data, whole-genome sequences (WGS), and population genetics and metagenomic approaches for multiple populations encompassing the entire spectrum of population size and demographic trajectories in the Florida Scrub-Jay (FSJ; Aphelocoma coerulescens).First, I investigate two subpopulations with contrasting demographic trajectories within the same metapopulation. Using BeadChip SNPs and demographic data for 288 FSJ sampled in 2000 and 2008, I show that in just a few generations after the onset of residential development, the declining population already exhibited lower site-based heterozygosity, higher levels of inbreeding, and increased relatedness compared to the intact population within a managed, biological preserve. This study emphasizes the importance of conservation intervention even in the early stages of a bottleneck.Expanding on this work, I use deep-coverage WGS for 241 individuals, sampled in the early 1990s and in 2017 from five focal populations to characterize in detail the impacts of varying population size and genetic isolation across the entire species. I also implement genome-wide and haplotype-based methods to show how historic and recent demographic histories have shaped current patterns of genetic variation in FSJ. This study highlights the complex interplay between effective population size and gene flow in mediating levels of genetic diversity and inbreeding. Finally, under the assumption that blood is sterile except in the case of pathogenic infections, I assess the potential impacts of reduced heterozygosity in 291 FSJ hosts on their blood-microbiome using a metagenomics approach. Contrary to expectations, I show a negative correlation between blood-microbial diversity and host inbreeding. Nonetheless, this study underscores the importance of microbiome research in conservation genetics and joins the mounting body of literature challenging the conventionally held belief of a sterile blood environment in healthy individuals.

Subject Added Entry-Topical Term  

Conservation biology.

Subject Added Entry-Topical Term  

Bioinformatics.

Subject Added Entry-Topical Term  

Genetics.

Subject Added Entry-Topical Term  

Evolution & development.

Index Term-Uncontrolled  

Demographic inference

Index Term-Uncontrolled  

Genomics

Index Term-Uncontrolled  

Inbreeding

Index Term-Uncontrolled  

Metagenomics

Index Term-Uncontrolled  

Population decline

Added Entry-Corporate Name  

Cornell University Ecology and Evolutionary Biology

Host Item Entry  

Dissertations Abstracts International. 85-03B.

Host Item Entry  

Dissertation Abstract International

Electronic Location and Access  

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Control Number  

joongbu:643805