Unknown Biases: Understanding How Anthropogenic Hybridization Impacts Genomic Diversity and Demographic Estimates

Area of Science:

• Genomics
• Conservation Biology
• Evolutionary Biology

Background:

• Anthropogenic hybridization between wild and domestic species is increasing.
• The mallard (Anas platyrhynchos) system exemplifies this with widespread hybridization due to game-farm releases.
• Feral mallards in Hawaii and New Zealand have hybridized with endemic ducks (Anas wyvilliana and Anas superciliosa superciliosa).

Purpose of the Study:

• To investigate the genomic consequences of hybridization between wild and domestic mallards.
• To compare genetic diversity and population structure across different ecoregions.
• To assess the impact of inbreeding and admixture on demographic inferences.

Main Methods:

• Whole-genome re-sequencing of domestic, wild, and hybrid mallards.
• Analysis of genetic diversity, runs of homozygosity, and ancestry.
• Demographic inference using genomic data.

Main Results:

• Wild mallard genomes exhibit higher genetic diversity and lower homozygosity than domestic lineages.
• Strongest correlation between ancestry and genetic statistics observed in North America, where stocking continues.
• In New Zealand and Hawaii, genetic drift and/or adaptive introgression decouple genetic statistics from ancestry.

Conclusions:

• Hybridization significantly alters genomic patterns in mallards.
• Conservation strategies must consider the genetic impacts of hybridization.
• Demographic inferences require careful interpretation when dealing with admixed or inbred populations.