Transgressive hybrids as hopeful holobionts

Area of Science:

• Evolutionary Biology
• Microbiome Research
• Holobiont Theory

Background:

• Hybridization can drive macroevolutionary change and introduce novel traits.
• The impact of hybridization on holobionts (host and microbiome) is less understood, with a prevailing view that it disrupts symbiosis and reduces fitness.
• This view may stem from studies on low-fitness hybrids, overlooking rare, successful 'hopeful holobionts'.

Purpose of the Study:

• To investigate the effects of hybridization on the gut and skin microbiota of an ecologically successful hybrid lizard, *Aspidoscelis neomexicanus*.
• To test if hybrid lizards exhibit host-associated (HA) microbiota distinct from their progenitor species.

Main Methods:

• Analysis of gut and skin microbiota in the hybrid lizard *Aspidoscelis neomexicanus*.
• Comparison of microbiota traits between hybrid lizards and their progenitor species.
• Assessment of correlations between microbiota restructuring and niche restructuring.

Main Results:

• Widespread evidence of transgressive segregation in hybrid microbiota phenotypes was observed.
• Microbiota restructuring in hybrids broadly correlated with niche restructuring.
• These findings suggest a link between HA microbiota traits and ecological success in hybrids.

Conclusions:

• Transgressive segregation of HA microbiota occurs in ecologically successful hybrids, suggesting hybridization can create novel, potentially beneficial holobiont phenotypes.
• Hybrid microbiota changes may promote niche expansion or shifts, potentially leading to ecological release from progenitors.
• This holobiont-level restructuring driven by hybridization could be a significant factor in evolutionary diversification.