When Clades Collide: Genomic Admixture in Blacklegged Ticks (Ixodes scapularis) From the Great Plains.
10 affiliations
- 1Department of Biology and Museum of Southwestern Biology, University of New Mexico, Albuquerque, New Mexico, USA.
- 2Department of Epidemiology, University of Nebraska Medical Center, Omaha, Nebraska, USA.
- 3Association of Public Health Laboratories, Bethesda, Maryland, USA.
- 4Nebraska Department of Health and Human Services, Lincoln, Nebraska, USA.
- 5School of Veterinary Medicine and Biomedical Sciences, University of Nebraska Lincoln, Lincoln, Nebraska, USA.
- 6Department of Pathology, Microbiology, and Immunology, University of Nebraska Medical Center, Omaha, Nebraska, USA.
- 7Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, Oklahoma, USA.
- 8Department of Veterinary Clinical Medicine, University of Illinois, Urbana-Champaign, Illinois, USA.
- 9Department of Entomology, Purdue University, West Lafayette, Indiana, USA.
- 10Department of Plant Pathology, Entomology and Microbiology, Iowa State University, Ames, Iowa, USA.
Abstract
Ixodes scapularis ticks transmit a number of pathogens important to human health, including Borrelia burgdorferi sensu stricto, the causative agent of Lyme disease. While I. scapularis is found across the Eastern United States, Lyme disease transmission is largely limited to the Northeast and Upper Midwest and is nearly absent in the South. This indicates that differences in northern versus southern clades of I. scapularis are associated with differences in Lyme disease transmission risk. Ixodes scapularis is undergoing range expansion, including into the Great Plains region of the United States. Determining where I. scapularis populations in the Great Plains originated can inform future risk of Lyme disease transmission in this region. In this study, we use a population genomics framework to characterize diversity, structure and B. burgdorferi infection rates of I. scapularis populations in the Great Plains region. We generated whole genome sequence data and single nucleotide polymorphism (SNP) datasets from I. scapularis ticks collected in Iowa, Kansas, Nebraska and South Dakota to compare to publicly available data from across the species' range. Our analysis of 200 I. scapularis SNP datasets indicated geographically well-defined populations that correspond to historical northern and southern ancestral clades of I. scapularis. Ticks from South Dakota, Iowa and northeastern Nebraska are genetically similar populations from the Upper Midwest, while ticks from Kansas are more genetically similar to ticks from the Southeast. Ticks collected in the east central region of Nebraska, however, represent an evenly admixed population of both northern and southern genomic backgrounds. Analysis of B. burgdorferi reads from genomic datasets shows ~50% infection rate in ticks from Iowa and northeastern Nebraska, whereas ticks from Kansas show no evidence of B. burgdorferi infection. Of note, evenly admixed ticks from the east central region of Nebraska also show no evidence of B. burgdorferi infection. These results provide further evidence that tick genomics may influence traits associated with B. burgdorferi infection status, and thus the potential for Lyme disease transmission. As the range of I. scapularis continues to expand, bringing historically isolated populations into contact, there is a clear need to understand the consequence of genomic admixture for B. burgdorferi transmission potential to inform future risk of Lyme disease in the United States.
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BibTeX
@article{herzog2026when,
title = {{When Clades Collide: Genomic Admixture in Blacklegged Ticks (Ixodes scapularis) From the Great Plains.}},
author = {Kaylee S Herzog and Zach Pella and Halie Smith and Dayna McCormick and Lily Nuss and Amanda Brinkworth and Sujata S Chaudhari and Kathryn Duncan and Kellee Sundstrom and Sydney Stein and Holly Black and Jose E Pietri and Ryan C Smith and Jeff Hamik and Roberto Cortiñas and Joseph R Fauver},
journal = {Molecular ecology},
year = {2026},
month = oct,
doi = {10.1111/mec.70577},
url = {https://europepmc.org/article/MED/42839832},
note = {CC BY},
}
RIS
TY - JOUR
TI - When Clades Collide: Genomic Admixture in Blacklegged Ticks (Ixodes scapularis) From the Great Plains.
AU - Kaylee S Herzog
AU - Zach Pella
AU - Halie Smith
AU - Dayna McCormick
AU - Lily Nuss
AU - Amanda Brinkworth
AU - Sujata S Chaudhari
AU - Kathryn Duncan
AU - Kellee Sundstrom
AU - Sydney Stein
AU - Holly Black
AU - Jose E Pietri
AU - Ryan C Smith
AU - Jeff Hamik
AU - Roberto Cortiñas
AU - Joseph R Fauver
PY - 2026
DA - 2026/10/01
JO - Molecular ecology
DO - 10.1111/mec.70577
UR - https://europepmc.org/article/MED/42839832
AB - Ixodes scapularis ticks transmit a number of pathogens important to human health, including Borrelia burgdorferi sensu stricto, the causative agent of Lyme disease. While I. scapularis is found across the Eastern United States, Lyme disease transmission is largely limited to the Northeast and Upper Midwest and is nearly absent in the South. This indicates that differences in northern versus southern clades of I. scapularis are associated with differences in Lyme disease transmission risk. Ixodes scapularis is undergoing range expansion, including into the Great Plains region of the United States. Determining where I. scapularis populations in the Great Plains originated can inform future risk of Lyme disease transmission in this region. In this study, we use a population genomics framework to characterize diversity, structure and B. burgdorferi infection rates of I. scapularis populations in the Great Plains region. We generated whole genome sequence data and single nucleotide polymorphism (SNP) datasets from I. scapularis ticks collected in Iowa, Kansas, Nebraska and South Dakota to compare to publicly available data from across the species' range. Our analysis of 200 I. scapularis SNP datasets indicated geographically well-defined populations that correspond to historical northern and southern ancestral clades of I. scapularis. Ticks from South Dakota, Iowa and northeastern Nebraska are genetically similar populations from the Upper Midwest, while ticks from Kansas are more genetically similar to ticks from the Southeast. Ticks collected in the east central region of Nebraska, however, represent an evenly admixed population of both northern and southern genomic backgrounds. Analysis of B. burgdorferi reads from genomic datasets shows ~50% infection rate in ticks from Iowa and northeastern Nebraska, whereas ticks from Kansas show no evidence of B. burgdorferi infection. Of note, evenly admixed ticks from the east central region of Nebraska also show no evidence of B. burgdorferi infection. These results provide further evidence that tick genomics may influence traits associated with B. burgdorferi infection status, and thus the potential for Lyme disease transmission. As the range of I. scapularis continues to expand, bringing historically isolated populations into contact, there is a clear need to understand the consequence of genomic admixture for B. burgdorferi transmission potential to inform future risk of Lyme disease in the United States.
SN - 0962-1083
SN - 1365-294X
ER -