Wildlife Conservation: Population Genetics Overview

Introduction to Population Genetics for Conservation

  • Course: AVBS3004: Wildlife Conservation
  • Instructor: A/Prof Catherine Grueber
  • Institution: The University of Sydney

Learning Outcomes

  • Key Terms: Understand and define the following terms related to conservation genetics:

    • Allele: Different versions of a gene found at a particular locus.
    • Allelic Richness: The number of different alleles present in a population. Higher richness indicates greater genetic diversity.
    • Heterozygosity: The presence of different alleles at one or more loci on homologous chromosomes. High heterozygosity is generally favorable for population health.
    • Inbreeding: Breeding between closely related individuals, often resulting in reduced genetic diversity.
    • Population Differentiation: Variability among populations in terms of genetic composition.
    • Population Structure: The arrangement of genetic variation within and among populations.

  • Key Processes:

    • Gene Flow: The transfer of genetic material (alleles) between populations, essential for maintaining genetic diversity and reducing the risk of extinction.
    • Genetic Rescue: The introduction of unrelated individuals to a population to enhance genetic diversity and mitigate inbreeding effects.

Gene Flow

  • Definition: Movement of alleles from one population to another.
  • Impact on Populations:
    • Can lead to genetic similarity between populations, thus reducing genetic structure.
    • Reduces measures of genetic differentiation.
  • Migrants vs. Genetic Migrants:
    • Migrants: Individuals that move between populations.
    • Genetic Migrants: Individuals that contribute to the gene pool.
  • Source-Sink Dynamics:
    • Considers population dynamics where high levels of unidirectional gene flow can place small source populations at risk.
  • Applications:
    • Natural Migration: Occurs without human intervention.
    • Artificial Migration: Can be intentional (conservation strategy) or unintentional (e.g. shipping ballast water).
  • Examples:
    • Rhino Translocation: A conservation effort in Manas National Park, India, led by WWF.
    • Ballast Water Shipping: Potentially unintentionally moves aquatic species between regions.

Genetic Rescue

  • Definition: The process of introducing new, unrelated individuals to a population to improve genetic diversity.
  • Goals:
    • Reduce the impact of inbreeding.
    • Increase the genetic diversity of the population.
    • Result in improved individual breeding success and survival.
    • Ultimately leads to an increased population growth rate and resilience, reducing extinction risk.
  • Considerations for Genetic Rescue:
    • Which populations are potential candidates for genetic rescue?
    • Where should new individuals be sourced from for effective translocation?

Importance of Genetic Diversity

  • Benefits:
    • Increased genetic diversity helps maintain the robustness of populations against diseases, environmental changes, and reproductive success.
    • Key to long-term survival of species, particularly those facing habitat fragmentation and loss.