Don Stewart's Lab

Molecular evolutionary genetics of bivalves and more

My students, collaborators and I study the unusual system of mitochondrial DNA inheritance in mussels, as well as population genetics and phylogenetics of many other species.


Research in Evolutionary Biology


Molecular evolutionary genetics of bivalves

My students, collaborators and I have been studying the unusual system of doubly uniparental inheritance of mitochondrial DNA in bivalves for 20+ years. My current NSERC Discovery grant is focused on this question. Current projects are underway with Dr. Sophie Breton ( Université de Montréal), Dr. Manuel Garrido-Ramos (Universidad de Granada) and Dr. Sidey Arias and Rebecca Quesada-Cespedes, Estación de Biología Marina, Puntarenas, Costa Rica).


Population genetics of species in Atlantic Canada

MSc student Brittni Scott is working on the population genetic structure of black bears in Nova Scotia. We are working with Soren Bondrup-Nielsen and others to study these fascinating large mammals.
Matthew Penney and I are working with Tim Rawlings (CBU) and industrial partners to study the genetic structure of holothurians in Atlantic Canada.


Genomics of shrews

With Dr. Aaron Shafer (Trent University), incoming student G. Jalilvand will explore the genome of the Maritime shrew, a Canadian Endemic species found only in Nova Scotia and New Brunswick.

Contact Us

Published Work

As of November 2018:

Papers in refereed journals.

74. Chase E, Robicheau B, Hoeh WR, Harris JL, Stewart DT, Breton S. 2018. The complete male-type mitochondrial genomes of the Fatmucket, Lampsilis siliquoidea, and the endangered Arkansas Fatmucket, Lampsilis powellii. Mitochondrial DNA Part B: Resources 4(1): 107-109.
73. Priest J, Stewart D, Boudreau M, Power J, Shutler D. 2018. First report of Angiostrongylus vasorum in coyotes in mainland North America. Veterinary Record. In press.
72. Renaut S, Guerra D, Hoeh WR, Stewart DT, Bogan AE, Ghiselli F, Milani L, Passamonti M, Breton S. 2018. Genome survey of the freshwater mussel Venustaconcha ellipsiformis (Bivalvia: Unionida) using a hybrid de novo assembly approach. Genome biology and evolution. 10(7):1637–1646. doi:10.1093/gbe/evy117
71. Robicheau B, Chase E, Hoeh WR, Harris JL, Stewart DT, Breton S. Evaluating the utility of the female-specific mitochondrial f-orf gene for population genetic, phylogeographic and systematic studies in freshwater mussels (Bivalvia: Unionida). PeerJ 6:e5007
70. Stewart DT, Rice A, Sinclair-Waters M, Bunker R, Robicheau B, Breton S. 2018. The distribution of male-transmitted mitochondrial DNA polymorphisms in Mytilus edulis mussels in south-western Nova Scotia. Canadian Journal of Zoology 96(6): 608-613,
69. Capt C, Renaut S, Ghiselli F, Milani L, Johnson N, Sietman BE, Stewart DT, Breton S. 2018. Deciphering the link between doubly uniparental inheritance of mtDNA and sex determination in bivalves: clues from comparative transcriptomics. Genome Biology and Evolution evy019,
68. Breton S, Bouvet K, Auclair G, Ghazal S, Sietman BE, Johnson N, Bettinazzi S, Stewart D, Guerra D. Accepted. The extremely divergent maternally- and paternally-transmitted mitochondrial genomes are co-expressed in somatic tissues of two freshwater mussel species with doubly uniparental inheritance of mtDNA. PLOS 1, 12 (8): e0183529 2017.
67. Robicheau B, Stewart DT, Breton S. 2017. Sequence motifs associated with the paternal transmission of mitochondrial DNA in the marine horse mussel, Modiolus modiolus. Gene 605: 32-42,
66. Guerra D, Plazzi F, Stewart DT, Bogan AE, Hoeh WR, Breton S. 2017. Evolution of sex-dependent mtDNA transmission in freshwater mussels. Scientific reports 7: 1551.
65. LeBlanc NM, Stewart DT, Pálsson S, Elderkin MF, Mittelhauser G, Mockford S, Paquet J, Robertson GJ, Summers RW, Tudor L, Mallory M. 2017. Population structure of Purple Sandpipers (Calidris maritima) as revealed by mitochondrial DNA and microsatellites. member and Evolution 1-18, DOI:10.1002/ece3.2927.
64. Robicheau B,  Powell A, Del Bel L, Breton S, Stewart DT. 2017. Evidence for extreme sequence divergence between the male‐and female‐transmitted mitochondrial genomes in the bivalve mollusc, Modiolus modiolus (Mytilidae). Journal of Zoological Systematics and Evolutionary Research 55(2): 89-97. doi: 10.1111/jzs.12160
63. Gusman A, Lecomte S, Stewart DT, Passamonti M, Breton S. 2016. Pursuing the quest for better understanding the taxonomic distribution of the system of doubly uniparental inheritance of mtDNA. PeerJ 4, p.e2760.
62. Mitchell A, Guerra D, Stewart DT, Breton S. 2016. In silico analyses of mitochondrial ORFans in freshwater mussels (Bivalvia: Unionoida) provide a framework for future studies of their origin and function. BMC Genomics (2016) 17:597. DOI 10.1186/s12864-016-2986-6
61. White S, Stewart DT, Hillier NK, Evans RC. 2016. Molecular identification of Mompha capella, a micro-lepidopteran predator of the endangered plant Crocanthemum canadense. Northeastern Naturalist 23(2):211-218. 2016 doi:
60. Breton S, Stewart DT. 2015. Atypical mitochondrial inheritance patterns in eukaryotes: a review. Genome. 10.1139/gen-2015-0090
59. Power J, Leblanc N, Bondrup-Nielsen S, Boudreau M, O’Brien M, Stewart DT. 2015. Spatial genetic and body size trends in Atlantic Canada Coyote (Canis latrans) populations. Northeastern Naturalist 22: 598-612.
58. Breton S, Milani L, Ghiselli F, Guerra D, Stewart DT, Passamonti M. 2014. A resourceful genome: updating the functional repertoire and evolutionary role of animal mitochondrial DNAs. Trends in Genetics 30:555-564. doi: 10.1016/j.tig.2014.09.002
57. Kelly JA, Avery TS, Stewart DT, Cutler CG, Gaul SO, MacKenzie KC, Hillier NK. 2013. Non-target Gelechiidae and Noctuidae attraction to Aroga trialbamaculella (Lepidoptera: Gelechiidae) pheromone-based trapping systems. Canadian Entomologist 145: 48-52.
56. Stewart DT, Jha M, Breton S, Hoeh WR, Blier PU. 2012. No effect of sperm interactions or egg homogenate on sperm velocity in the blue mussel, Mytilus edulis (Bivalvia: Mytilidae). Canadian Journal of Zoology. 90: 1291-1296, 10.1139/z2012-099.
55. Stanton LM, Hoeh WR, McAlpine DF, Hebda A, Stewart DT. 2012. mtDNA and AFLP markers demonstrate limited genetic differentiation within the Pyganodon cataracta/ Pyganodon fragilis freshwater mussel complex in Atlantic Canada. Canadian Journal of Zoology. 90: 1307-1319, 10.1139/z2012-100.
54. Breton S, Ghiselli F, Passamonti M, Milani L, Stewart DT, Hoeh WR. 2011. Evidence for a fourteenth mtDNA-encoded protein in the female-transmitted mtDNA of marine mussels (Bivalvia: Mytilidae). PLoS ONE 6(4): e19365. doi:10.1371/journal.pone.0019365
53. Mycroft E, Shafer ABA, Stewart DT. 2011. Cytochrome b sequence variation in water shrews (Sorex palustris) from eastern and western North America. Northeastern Naturalist 18:497-508.
52. Breton S, Stewart DT, Shepardson S, Trdan RJ, Bogan AE, Chapman EG, Ruminas AJ, Piontkivska H, Hoeh WR. 2011. Novel protein genes in animal mtDNA: a new sex determination system in freshwater mussels (Bivalvia: Unionoida)? Molecular Biology and Evolution doi: 10.1093/molbev/msq345.
51. Breton S, Stewart DT, Hoeh WR. 2010. Characterization of a mitochondrial ORF from the gender-associated mtDNAs of Mytilus spp. (Bivalvia: Mytilidae): identification of the "missing" ATPase 8 gene. Marine Genomics 3: 11-18.
50. Doucet-Beaupré H, Breton S, Chapman EG, Blier PU, Bogan AE, Stewart DT, Hoeh WR. 2010. Mitochondrial phylogenomics of the Bivalvia (Mollusca): searching for the origin and mitogenomic correlates of doubly uniparental inheritance of mtDNA. BMC Evolutionary Biology 10:50 doi:10.1186/1471-2148-10-50
49. Breton S, Doucet-Beaupré H, Stewart DT, Piontkivska H, Karmakar M, Bogan AE, Blier PU, Hoeh, W.R. 2009. Comparative mitochondrial genomics of freshwater mussels (Bivalvia: Unionoida) with doubly uniparental inheritance of mtDNA: gender-specific open reading frames and putative origins of replication. Genetics 183: 1575-1589.
48. Chakrabarti R, Shepardson SP, Karmakar M, Trdan RJ, Walker JM, Shandilya R, Stewart DT, Vijayaraghavan S, Hoeh WR. 2009. Extra-mitochondrial localization and likely reproductive function of a female transmitted cytochrome c oxidase subunit II protein. 2009. Development, Growth and Differentiation. 51: 511-519
47. Breton S, Stewart DT, Blier PU. 2009. Role-reversal of gender-associated mitochondrial DNA affects mitochondrial function in Mytilus edulis (Bivalvia: Mytilidae). Journal of Experimental Zoology Part B: Molecular and Developmental Evolution 312:108-117  
46. Shafer ABA, Williams GR, Shutler, D., Rogers, R.E.L., Stewart DT 2009. Cophylogeny of Nosema (Microsporidia: Nosematidae) and bees (Hymenoptera: Apidae) suggests cospeciation and a host-switch. Journal of Parasitology. Journal of Parasitology 95: 198-203.  
45. Cowan KM, Shutler D, Herman TB, Stewart DT. 2009. Splenic mass of masked shrews, Sorex cinereus, in relation to body mass, sex, age, date, and bladder nematode, Liniscus (=Capillaria) maseri, infection. Journal of Parasitology 95:228-230.
44. Shafer ABA, Scott FW, Petersen SD, Rhymer JM, Stewart DT. 2008. Following the SINEs: a taxonomic revision of the of the long-tailed shrew complex, Sorex dispar and S. gaspensis. Journal of Mammalogy. 89:1421-1427.
43. Chapman EG, Piontkivska O, Walker JM, Stewart DT, Curole JP, Hoeh WR. 2008. Extreme primary and secondary structure variability in the novel extension of the male-transmitted cytochrome c oxidase subunit II protein in freshwater mussels: evidence for site-specific positive and domain-specific purifying selection.  BMC Evolutionary Biology 8:165 doi:10.1186/1471-2148-8-165.
42. Dawe K, Shafer ABA, Herman TB and Stewart DT. 2009. Diffusion of nuclear and mitochondrial genes across a zone of secondary contact in the maritime shrew, Sorex maritimensis: implications for the conservation of a Canadian endemic mammal. Conservation Genetics. 10:851-857.  
41. Shafer ABA, Stewart DT. 2008. A population crash of the red-backed vole (Myodes gapperi) in Nova Scotia inferred from bycatch of the long-tailed shrew (Sorex dispar). Northeastern Naturalist. 15: 626-629.
40. Jha M, Côté J, Hoeh WR, Blier PU, Stewart DT. 2008. Sperm motility in Mytilus edulis in relation to mitochondrial DNA polymorphisms: implications for the evolution of doubly uniparental inheritance in bivalves. Evolution 62: 99-106
39. Breton S, Doucet-Beaupré H, Stewart DT, Hoeh WR, Blier PU. 2007. The unusual system of doubly uniparental inheritance of mtDNA: Isn’t one enough? Trends in Genetics 23:464-475
38. Williams GR, Shafer ABA, Rogers REL, Shutler D, Stewart DT. 2008. First detection of Nosema ceranae, a microsporidian parasite of European honey bees (Apis mellifera), in Canada and central U.S.A. Journal of Invertebrate Pathology. 97:189-192.
37. Chakrabarti, R., Walker JM, Chapman EG, Shepardson SP, R.J. Trdan, Curole JP, G.T. Watters, Stewart DT, S. Vijayaraghavan and Hoeh WR. 2007. Reproductive function for a C-terminus extended, male-transmitted cytochrome c oxidase subunit II protein expressed in both spermatozoa and eggs. FEBS Letters. 581: 5213-5219.
36. Shafer ABA, Stewart DT. 2007. Phylogenetic relationships within the genus Sorex (Insectivora: Soricidae) inferred from Bayesian analysis using combined cytochrome b sequences and SINE data. Molecular Phylogenetics and Evolution. 44: 192-203
35. Cowan KM, Shutler D, Herman TB, Stewart DT. 2007. Extreme male-biased bladder nematode [Liniscus (=Capillaria) maseri] infection in masked shrews, Sorex cinereus. Journal of Mammalogy. 88(6): 1539-1543.
34. Shafer ABA, Stewart DT. 2006. A novel location for the long-tailed shrew (Sorex dispar) in Nova Scotia. The Northeastern Naturalist. 14:603-608.
33. Petersen SD and Stewart DT. 2006. Biogeography and conservation genetics of southern flying squirrels, Glaucomys volans. Journal of Mammalogy 87:153-160.
32. Lavers A, Petersen SD, Herman TB, Stewart DT. 2006. Delineating the range of a disjunct population of southern flying squirrels. American Midland Naturalist 155:188-196.
31. Breton S, Burger G, Stewart DT, Blier PU. 2006. Comparative analysis of gender-associated, complete mitochondrial genomes in marine mussels (Mytilus spp.) Genetics 172: 1107-1119.
30. Chakrabarti R, Walker JM, Stewart DT, Trdan RJ, Vijayaraghavan S, Curole JP, Hoeh WR 2006. Presence of a unique male-specific extended C-terminus to the cytochrome c oxidase subunit II protein coded by the male-transmitted mitochondrial genome of Venustaconcha ellipsiformis (Bivalvia: Unionoidea). FEBS Letters 580(3):862-6.
29. Knock E, Petersen SD and Stewart DT. 2005. Differential display reverse transcription PCR applied to male Mytilus edulis mussels with two distinct mitochondrial DNA types. Biochemical Systematics and Ecology 33:715-724.
28. Everett E, Williams P, Gibson G, Stewart DT. 2004. Mitochondrial  DNA polymorphisms and sperm fitness in Mytilus edulis (Bivalvia: Mytilidae) Journal of Experimental Zoology 301A: 906-910.
27. Perry ND, Stewart DT, Madden EM, Maier TJ. 2004. The first Montana state record for the Arctic Shrew (Sorex arcticus), and two range extensions for the newly recognized Maritime Shrew (Sorex maritimensis). Canadian Field-Naturalist 118:400-405.
26. Griffiths K, Stewart DT. 2004. New record and phylogenetic analysis of Anthomyia pluvialis in Nova Scotia. Northeastern Naturalist 11:189-196.  
25. VanderKloet SP, Baltzer JL, Appleby JH, Evans RC, Stewart DT. 2004. A re-examination of the taxonomic boundaries of Symphysia. Taxon 5: 91-98.
24. Stewart DT, McPherson M, Robichaud J, Fumagalli L.  2003. Are there two species of pygmy shrews? Revisiting the question using mitochondrial DNA cytochrome b sequence data. Canadian Field-Naturalist. 31:573-580.
23. MacPherson IS, Stewart DT. 2003. Characterisation of a unique dipeptidase allele in an insular population of masked shrews, Sorex cinereus (Insectivora: Soricidae). Biochemical Systematics and Ecology. 31:573-580.
22. Hoeh, WR, Stewart DT, Guttman SI. 2002. High fidelity of mtDNA transmission under the doubly uniparental mode of inheritance in freshwater mussels (Bivalvia: Unionoidea). Evolution 56:2252-2261.
21. Stewart DT, Perry ND, Fumagalli L. 2002. The maritime shrew, Sorex maritimensis (Insectivora: Soricidae): a newly recognized, Canadian endemic. Canadian Journal of Zoology. 80: 94-99.
20. Dalziel AC, Stewart DT. 2002. Tissue specific expression of male transmitted mitochondrial DNA and its implications for rates of molecular evolution in Mytilus mussels (Mytilidae, Bivalvia). Genome. 45:1-8.  
19. Jennings V, Stewart D. 2000. Ecology and evolution of wall-dwelling organisms. American Biology Teacher. 62: 429-435.  
18. Fumagalli L, Taberlet P, Stewart DT, Gielly L, Hausser J, Vogel P. 1999. Molecular phylogeny and evolution of Sorex shrews (Soricidae: Insectivora) inferred from mtDNA sequence data. Molecular Phylogenetics and Evolution 11:222-235.
17. Garrido-Ramos M, Stewart DT, Sutherland BW, Zouros E. 1998. The distribution of male-transmitted and female-transmitted mitochondrial DNA types in somatic tissues of blue mussels: Implications for the operation of doubly uniparental inheritance of mitochondrial DNA. Genome 41: 818-824
16. Sutherland BW, Stewart DT, Kenchington ER, Zouros E. 1998. The fate of paternal mitochondrial DNA in developing female mussels, Mytilus edulis. Genetics 148: 341-348.
15. Stewart DT, Baker AJ. 1997. A phylogeny of some taxa of masked shrews (Sorex cinereus) based on mitochondrial DNA D-loop sequences. Journal of Mammalogy 78: 361-376.
14. Hoeh WR, Stewart DT, Sutherland BS, Zouros E.  1997. Phylogenetic evidence for role-reversals of gender-associated mitochondrial DNA in Mytilus (Bivalvia: Mytilidae). Molecular Biology and Evolution 14: 959-967.
13. Fumagalli L, Hausser J, Taberlet P, Gielly L, Stewart DT. 1997. Phylogenetic structure of the Holarctic Sorex araneus group and its relationship to S. samniticus, as inferred from mtDNA sequences. Hereditas 125: 191-199.  
12. Hoeh WR,  Stewart DT, Sutherland BW, Zouros E. 1996. Multiple origins of gender- associated mitochondrial DNA lineages in bivalves (Mollusca).  Evolution 50: 2276-2286.  
11. Stewart DT, Kenchington E, Singh R, Zouros E.  1996. Degree of selective constraint as an explanation of the different rates of evolution of gender-specific mitochondrial DNA lineages in the mussel Mytilus. Genetics 143:1349-1357.
10. Saavedra C, Stewart DT, Stanwood RR, Zouros E.  1996.  Species specific segregation of gender-associated mitochondrial DNA types in an area where two mussel species (Mytilus edulis and Mytilus trossulus) hybridize. Genetics 143:1359-1367.
9. Hoeh WR, Stewart DT, Sutherland BW, Zouros E. 1996. Cytochrome c oxidase sequence comparisons suggest an unusually high rate of mitochondrial DNA evolution in Mytilus (Mollusca: Bivalvia). Molecular Biology and Evolution 13: 418-421.
8. Stewart DT, Saavedra C, Stanwood RR, Ball AO, Zouros E. 1995. Male and female mitochondrial DNA lineages in the Blue Mussel Mytilus. Molecular Biology and Evolution 12: 735-747.  
7. Stewart DT, Baker AJ. 1994. Patterns of sequence variation in the mitochondrial D-loop region of shrews. Molecular Biology and Evolution 11: 9-21.
6. Stewart DT, Baker AJ. 1994. Evolution of mtDNA D-loop sequences and their use in phylogenetic studies of shrews in the subgenus Otisorex (Sorex: Soricidae: Insectivora). Molecular Phylogenetics and Evolution 3: 38-46.
5. Stewart DT, Baker AJ, Hindocha SP. 1993. Genetic differentiation and population structure in Sorex haydeni and S. cinereus. Journal of Mammalogy 74: 21-32.
4. Stewart DT. 1993. Sexual dimorphism in thick-billed murres, Uria lomvia. Canadian Journal of Zoology 71: 346-351.
3. Stewart DT, Baker AJ. 1992. Genetic differentiation and biogeography of the masked shrew in Atlantic Canada. Canadian Journal of Zoology 70: 106-114.
2. Teferi T, Herman TB, Stewart DT. 1992. Breeding biology of an insular population of the masked shrew (Sorex cinereus) in Nova Scotia. Canadian Journal of Zoology 70: 62-66.
1. Stewart DT, Herman TB, Teferi T. 1989. Littoral feeding in a high-density insular population of Sorex cinereus. Canadian Journal of Zoology 67: 2074-2077.


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Department of Biology

Acadia University

Wolfville, NS Canada

B4P 2R6