Rangewide molecular structuring in the Utah sucker (Catostomus ardens)

Area of Science:

• Ecology
• Evolutionary Biology
• Genetics

Background:

• The Utah sucker (Catostomus ardens) is endemic to the Bonneville Basin and upper Snake River.
• Hybridization with the endangered June sucker (Chasmistes liorus mictus) is suspected in Utah Lake.
• Previous studies recognized morphological variation but not major genetic subdivisions.

Purpose of the Study:

• To investigate genetic population structure in Utah suckers.
• To identify genetic divergence between Utah suckers and June suckers.
• To explore the role of historical hydrology and ecological selection in shaping sucker diversity.

Main Methods:

• Mitochondrial DNA sequencing was used to analyze genetic divergence.
• Phylogenetic analysis was employed to reconstruct evolutionary relationships.
• Morphological data was compared with genetic findings.

Main Results:

• A major genetic subdivision (4.5% mitochondrial divergence) was discovered between Utah sucker populations in the Bonneville Basin and the Snake River drainage.
• Populations east of the Wasatch Mountains clustered with Snake River populations, suggesting ancient hydrologic connections.
• Evidence of population isolation within the Bonneville Basin, linked to Pleistocene sub-basins, was found.
• No molecular evidence for deep divergence or hybridization between Utah and June suckers in Utah Lake was detected.

Conclusions:

• Morphological and molecular variation in Utah suckers do not always align, indicating different evolutionary pressures.
• Ecological selection may be responsible for the observed morphological differences between Utah and June suckers in Utah Lake.
• The findings highlight the complexity of species diversity, influenced by both neutral and adaptive genetic variation.