1. Cryptic Sucker Species of the Northeast
Patrick Alford, Dr. Evon Hekkala
Calder Summer Undergraduate Research Program, Fordham University
Abstract
Based on taxonomic history as well as previous sampling and genetic analysis of sucker populations, there are thought to be two species coexisting in New York’s Adirondack region. The summer sucker (Catostomus utawana) was recently redescribed (Morse et al.) as a species of fish endemic to New York’s Adirondack region characterized by small size and late spawning. Field surveys have shown that it co-exists in several ponds with the common white sucker (C. commersoni). Using genetic methods, we compared individuals of various populations to evaluate taxonomic identity and geographic distribution of suckers in the Adirondack region of NY State. We used nuclear and mitochondrial genetic marker sets in an attempt to investigate whether the recent taxonomic revision of suckers in the Adirondack region is supported by molecular data.
Methods
Collected 118 fin clip samples from 20 ponds in the Adirondacks using gill nets, fyke nets, and electroshockers. 
Extracted fin clip samples using Qiagen DNA extraction kits.
Amplified DNA examining CytB gene region as well as nuclear intron regions of IRBP and Rag1.
Sequenced CytB gene region of 96 samples through Macrogen.
Compared CytB haplotypes among all individuals.
Aligned and edited sequences using Sequencher.
Haplotype network was constructed using Network.
Mapped population haplotype distribution with GIS.
Fig. 1 Haplotype network displaying all individuals as two distinct haplotypes (yellow corresponds to haplotype A while blue corresponds to haplotype G) based on the CytB gene region. As shown by the red numbers, the fixed base pair difference occurs around the 828th base pair of the CytB region (not exact due to uncertainty of beginning of gene).
Fig. 2 Map showing the distribution of the haplotype A populations in red, the haplotype G populations in blue, and the mixed populations in purple. The Hudson River Drainage, Champlain Watershed, and Raquette Drainage are outlined in orange, green, and black, respectively.
Introduction
Ecological importance of Suckers lies in their ability to indicate water quality (Schofield and Driscoll, 1987).
Historical taxonomic reassignment within the New York State Adirondack region led to confusion of sucker taxonomy within the Adirondacks.
Initial taxonomy of Hudson River drainage describes species, Catostomus hudsonius (Morse et al.).
Later taxonomic analyses described the longnose sucker and white sucker independently populating the same region
The species, Catostomus utawana, was also described, having many re-descriptions and taxonomic classifications (Morse et al.).
This project compared genetic variation patterns among populations from various water sources of the Adirondack Region using the Cytochrome B gene region.
Fig.3 Two clusters inferred from Structure analysis of 249 suckers from 20 sites throughout upstate New York from previous sampling. Each color represents an inferred genotype cluster, and each individual is represented by a vertical line colored according to its probability of assignment to each cluster. Population one represents individuals exhibiting the haplotype A lineage, while population two represents the haplotype G lineage.
Discussion
Our analyses suggest a possible distinct population segment of white sucker within the northeast. However, additional, nuclear makers are needed to confirm the genetic distinctness of this group. Among samples populations, individuals with CytB haplotype G are predominantly contained to the headwaters of the Hudson River Drainage and Raquette Drainage. Based on patterns observed in other fish taxa found in the Adirondack High Peaks region (Hare et al.), the current distribution of the two sucker haplotypes may correspond to a geographic distribution resulting from post glacial isolation.
Results
Cyt B sequencing and haplotype network both support two haplotypes of suckers based on a single fixed base pair difference: haplotype A and haplotype G.
Populations where both haplotype A and haplotype G are found are rare (2 out of 20 populations).
Nuclear intron regions, IRBP and Rag1, both failed to optimize in PCR.