Tuberculosis Susceptibility and Inbreeding Depression Hinder Ex Situ Conservation in a Critically Endangered...

Area of Science:

• Conservation genetics
• Avian biology
• Wildlife disease ecology

Background:

• The white-winged wood duck (WWWD) is critically endangered due to population declines and habitat fragmentation in Southeast Asia.
• Captive breeding programs aim to conserve WWWD but are challenged by high susceptibility to avian tuberculosis (TB).

Purpose of the Study:

• To investigate genome-wide diversity patterns in WWWD to understand demographic history, inbreeding, and TB susceptibility.
• To identify genetic factors contributing to TB susceptibility in WWWD.

Main Methods:

• Genome-wide diversity analysis
• Demographic and phylogeographic modeling
• Comparative gene expression analysis between WWWD and resistant redhead ducks.

Main Results:

• WWWD populations exhibit extremely low genetic diversity, with captive birds showing further erosion.
• Wild birds retain higher Major Histocompatibility Complex (MHC) diversity, crucial for immune function.
• Inbreeding correlates with earlier mortality from TB infections, indicating inbreeding depression.
• Comparative genomics identified potential mechanisms underlying TB susceptibility in WWWD.

Conclusions:

• Long-term population declines preceded recent anthropogenic impacts, a pattern seen in related forest-dependent species.
• Ex situ conservation must prioritize managing inbreeding and preserving functional genetic diversity.
• Genomic insights can guide future management strategies for WWWD conservation and mitigate TB risks.