Complexity of schistosome vector bulinine snails in Kenya: Insights from nuclear genome size variation, complete mitochondrial genome sequence, and morphometric analysis.

Investigations of nuclear genome size, complete mitochondrial genome (mitogenome) sequence, and morphometrics were conducted on specimens of Bulinus snails (Gastropoda: Planorbidae) collected from 14 locations across the east coast, central Kenya, and western Kenya around the Lake Victoria region (N...

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Main Authors: Si-Ming Zhang, Coen M Adema, Mohamed R Habib, Abdelmalek Lekired, Marijan Posavi, Martina R Laidemitt, Geoffrey M Maina, Ibrahim N Mwangi, Joseph M Kinuthia, Martin W Mutuku, Eric S Loker
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2025-07-01
Series:PLoS Neglected Tropical Diseases
Online Access:https://doi.org/10.1371/journal.pntd.0013305
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author Si-Ming Zhang
Coen M Adema
Mohamed R Habib
Abdelmalek Lekired
Marijan Posavi
Martina R Laidemitt
Geoffrey M Maina
Ibrahim N Mwangi
Joseph M Kinuthia
Martin W Mutuku
Eric S Loker
author_facet Si-Ming Zhang
Coen M Adema
Mohamed R Habib
Abdelmalek Lekired
Marijan Posavi
Martina R Laidemitt
Geoffrey M Maina
Ibrahim N Mwangi
Joseph M Kinuthia
Martin W Mutuku
Eric S Loker
author_sort Si-Ming Zhang
collection DOAJ
description Investigations of nuclear genome size, complete mitochondrial genome (mitogenome) sequence, and morphometrics were conducted on specimens of Bulinus snails (Gastropoda: Planorbidae) collected from 14 locations across the east coast, central Kenya, and western Kenya around the Lake Victoria region (November 2013 and January 2024). Flow cytometry measurements of DNA content (C-value) revealed unexpected variation in nuclear genome size, with diploid Bulinus africanus and B. forskalii species groups showing C-values ranging from 0.76 to 1.98 pg, while tetraploid B. truncatus had a C-value of 1.82 pg. Additionally, C-values for six B. globosus specimens from different localities ranged from 1.43 to 1.98 pg. These findings suggest that bulinine snails, particularly the B. africanus species group, have undergone genome expansion, whole genome duplication (polyploidization), or both, which have not been previously recognized. Next-generation sequencing was performed to determine and annotate 14 complete mitogenome sequences. Despite the well-conserved arrangement of protein-coding genes, two versions of mtDNA genome structure, distinguished by the tRNA-D (Asp) location, were found, designated as DCF (Asp-Cys-Phe) type (in the B. forskalii group and the B. truncatus/tropicus complex) and CF (Cys-Phe) type (in the B. africanus group). Phylogenetic analyses based on complete mtDNA sequences of bulinines from Kenya, along with cytochrome c oxidase subunit I (COX1) sequences from various localities across Africa, contributed to resolving species identities and provided further support for the presence of multiple or cryptic species in the taxon B. globosus. A landmark-based morphometric analysis was ineffective in distinguishing these species. This study reveals unexpected nuclear genome size variation, provides new mitogenome sequences, and highlights the limitations of morphological analysis. It offers valuable insights into the cytogenetics, polyploidy, genomics, taxonomy, and evolution of bulinines, which serve as intermediate hosts for schistosomes responsible for human urogenital schistosomiasis and intestinal schistosomiasis in domestic and wild mammals.
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spelling doaj-art-45178d5621a1437c84d61818e23e2c4f2025-08-20T03:25:27ZengPublic Library of Science (PLoS)PLoS Neglected Tropical Diseases1935-27271935-27352025-07-01197e001330510.1371/journal.pntd.0013305Complexity of schistosome vector bulinine snails in Kenya: Insights from nuclear genome size variation, complete mitochondrial genome sequence, and morphometric analysis.Si-Ming ZhangCoen M AdemaMohamed R HabibAbdelmalek LekiredMarijan PosaviMartina R LaidemittGeoffrey M MainaIbrahim N MwangiJoseph M KinuthiaMartin W MutukuEric S LokerInvestigations of nuclear genome size, complete mitochondrial genome (mitogenome) sequence, and morphometrics were conducted on specimens of Bulinus snails (Gastropoda: Planorbidae) collected from 14 locations across the east coast, central Kenya, and western Kenya around the Lake Victoria region (November 2013 and January 2024). Flow cytometry measurements of DNA content (C-value) revealed unexpected variation in nuclear genome size, with diploid Bulinus africanus and B. forskalii species groups showing C-values ranging from 0.76 to 1.98 pg, while tetraploid B. truncatus had a C-value of 1.82 pg. Additionally, C-values for six B. globosus specimens from different localities ranged from 1.43 to 1.98 pg. These findings suggest that bulinine snails, particularly the B. africanus species group, have undergone genome expansion, whole genome duplication (polyploidization), or both, which have not been previously recognized. Next-generation sequencing was performed to determine and annotate 14 complete mitogenome sequences. Despite the well-conserved arrangement of protein-coding genes, two versions of mtDNA genome structure, distinguished by the tRNA-D (Asp) location, were found, designated as DCF (Asp-Cys-Phe) type (in the B. forskalii group and the B. truncatus/tropicus complex) and CF (Cys-Phe) type (in the B. africanus group). Phylogenetic analyses based on complete mtDNA sequences of bulinines from Kenya, along with cytochrome c oxidase subunit I (COX1) sequences from various localities across Africa, contributed to resolving species identities and provided further support for the presence of multiple or cryptic species in the taxon B. globosus. A landmark-based morphometric analysis was ineffective in distinguishing these species. This study reveals unexpected nuclear genome size variation, provides new mitogenome sequences, and highlights the limitations of morphological analysis. It offers valuable insights into the cytogenetics, polyploidy, genomics, taxonomy, and evolution of bulinines, which serve as intermediate hosts for schistosomes responsible for human urogenital schistosomiasis and intestinal schistosomiasis in domestic and wild mammals.https://doi.org/10.1371/journal.pntd.0013305
spellingShingle Si-Ming Zhang
Coen M Adema
Mohamed R Habib
Abdelmalek Lekired
Marijan Posavi
Martina R Laidemitt
Geoffrey M Maina
Ibrahim N Mwangi
Joseph M Kinuthia
Martin W Mutuku
Eric S Loker
Complexity of schistosome vector bulinine snails in Kenya: Insights from nuclear genome size variation, complete mitochondrial genome sequence, and morphometric analysis.
PLoS Neglected Tropical Diseases
title Complexity of schistosome vector bulinine snails in Kenya: Insights from nuclear genome size variation, complete mitochondrial genome sequence, and morphometric analysis.
title_full Complexity of schistosome vector bulinine snails in Kenya: Insights from nuclear genome size variation, complete mitochondrial genome sequence, and morphometric analysis.
title_fullStr Complexity of schistosome vector bulinine snails in Kenya: Insights from nuclear genome size variation, complete mitochondrial genome sequence, and morphometric analysis.
title_full_unstemmed Complexity of schistosome vector bulinine snails in Kenya: Insights from nuclear genome size variation, complete mitochondrial genome sequence, and morphometric analysis.
title_short Complexity of schistosome vector bulinine snails in Kenya: Insights from nuclear genome size variation, complete mitochondrial genome sequence, and morphometric analysis.
title_sort complexity of schistosome vector bulinine snails in kenya insights from nuclear genome size variation complete mitochondrial genome sequence and morphometric analysis
url https://doi.org/10.1371/journal.pntd.0013305
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