Tia-Lynn Ashman

  • Distinguished Professor
  • Evolutionary ecology

Contact

Office: (412) 624-0984
Lab: (412) 624-0984
215 Clapp Hall
4249 Fifth Avenue
Pittsburgh, PA 15260

Current work in the lab revolves around three major foci: 1) The contribution of polyploidy to functional and genomic biodiversity; 2) Ecological and evolutionary studies of separate sexes and sex chromosomes; and 3) The factors that shape plant-pollinator interactions, and the consequences for phenotypic evolution, microbial-plant interactions and community structure of flowering plants.

How does polyploidy contribute to biodiversity?

Most, if not all, flowering plants are polyploids, and as such polyploidy is identified as an important mode of speciation in plants and a main driver of biological adaptation and range expansion. As a consequence, it may be key to plant evolutionary/ecological potential to respond to environmental change. However, exactly how polyploidy contributes to biodiversity and which genomic mechanisms or functional traits underlie the success of polyploids remain unanswered questions. We are using Fragaria as a model system to address these long standing questions and test fundamental hypotheses on how polyploidy contributes to biodiversity. With an international group of collaborators (China and USA) we are conducting an integrated study of genetic, functional (phenotypic and transcriptomic) and phylogenomic biodiversity. We aim to produce an authoritative understanding of whether similarities in functional diversity and ecological amplitude of polyploid species are the result of the same patterns (‘rules’) of genetic diversity, chromosome structure or gene expression in a polyploid genome or whether multiple genetic and genomic pathways could lead to successful responses to environmental change.

How can plants provide key insight into the nature of the evolving sex chromosome?

Our extensive ecological and genetic work on the evolution of separate sexes (dioecy) in strawberry (Fragaria) places us in a unique position to evaluate the dynamics of sex chromosome evolution--not only the crucial first steps but also whether other processes, usually ascribed to later stages, take place in younger sex chromosomes as well. Despite numerous studies in a wide range of organisms, the very earliest step in sex chromosome evolution -- from two linked but recombining loci to suppression of recombination between them (and thus the transition from subdioecy to dioecy) --remains unexplored. We are merging genetic, genomic and bioinformatic approaches with ecology and phylogeny to test hypotheses regarding recombination suppression, sequence divergence and selection for sexually antagonistic genes linked to sex. We are utilizing several species within the sexually variable clade of Fragaria to gain transformative insight into early sex chromosome evolution, as well as the unique roles of hybridization and  polyploidy in the transition from hermaphroditism to separate sexes.

How do pollinators mediate plant-plant and plant-microbe(viral) interactions and in turn how do these affect pollination sufficiency?

Understanding the nature of plant-plant-pollinator interactions (i.e., whether plants compete for pollinators or facilitate each other’s pollination) and how they translate into pollination sufficiency and ultimately plant population persistence is central to our understanding of the generation and maintenance diversity in plant communities.  Shared pollinators also mediate interactions between flowers and microbes (and viruses) that can affect plant fitness both positively and negatively.

Work in both of these areas is even more relevant in the Anthropocene as native pollinator-plant interactions are at risk from land-use and climate change, and as species invasions reshape interaction networks.  One current emphasis of the lab is to understand how pre- and post-pollination interactions contribute to plant community assembly and coexistence, and how pollinator networks that include intentional and spontaneous plants lead to novel plant-pathogen interactions and/or disrupt microbial mutualisms. We are addressing these questions in flowering communities in native habitats of California, Hawaii and Mexico and urban contexts of Pittsburgh and Germany.

What drives floral trait evolution and plant speciation?

We seek to understand both the context-dependency of pollinator-mediated selection and the direct effects of non-pollinator agents of selection on floral traits.  Members of my lab and I do so by considering the ways that biotic (antagonists or soil mutualisms) or abiotic (soil conditions) modify plant-pollinator interactions as well as taking a holistic approach to floral evolution and exposing novel agents of selection.We approach these issues using mechanistic ecological experiments, geographic surveys and phylogenetically-controlled large scale comparisons. We are keenly interested in addressing the multivariate functional floral phenotype and all sensory modalities of pollinators have addressed evolution of less well-studied characters, such as floral fragrance, longevity, reward chemistry, and ultra-violet color patterns. Each of these has been implicated in mediating interactions with pollinators but also may be under selection via a variety of other agents (herbivores, pathogens, mycorrhizal fungi, rhizobia, foliar endophytes, soil chemistry, UV radiation) either directly or indirectly, and understanding how these interactions lead to evolution of floral phenotype, mating system and reproductive isolation is a main agenda in the lab.

E-mail Lab

Johnson, A., A. Fetters, and T

Johnson, A., A. Fetters, and T-L., Ashman. Considering the unintentional consequences of pollinator gardens for urban native plants: Is the road to extinction paved with good intentions? New Phytologist 215(4):1298-1305 

Sabath, N., E.E. Goldberg, L. Glick, M. Einhorn

Sabath, N., E.E. Goldberg, L. Glick, M. Einhorn, T-L. Ashman, R. Ming, S.P. Otto, J. Vamosi, and I. Mayrose.  2016. Dioecy does not consistently accelerate or slow lineage diversification across multiple genera of angiosperms. New Phytologist 209(3):1290-300

Wei, N,. J. Tennessen, A. Liston and T-L. Ashma

Wei, N,. J. Tennessen, A. Liston and T-L. Ashman. 2017 Present-day sympatry belies evolutionary origin of a high-order polyploid. New Phytologist 216:279-290 

Goldberg, E.E., S.P. Otto, J. Vamosi, I. Mayros

Goldberg, E.E., S.P. Otto, J. Vamosi, I. Mayrose, R. Ming, and T-L. Ashman. 2017. Macroevolutionary synthesis of flowering plant sexual systems.  Evolution 71(4):898-912 

Koski, M., and T-L. Ashman. 2015. An altitudina

Koski, M., and T-L. Ashman. 2015. An altitudinal cline in UV floral pattern corresponds with behavioral change of the generalist pollinator assemblage.  Ecology  96(12):3343-53.  

Arceo-Gómez, G., L. Abdala-Roberts, A. Jankowia

Arceo-Gómez, G., L. Abdala-Roberts, A. Jankowiak, C. Kohler, G.A., Meindl, V. Parra-Tabla, V., T-L. Ashman and C. Alonso. 2016. Patterns of among- and within-species variation in heterospecific pollen receipt: the importance of ecological generalization. American Journal of Botany in press

Wipf, H., Meindl, G. A., and T-L. Ashman. 2016.

Wipf, H., Meindl, G. A., and T-L. Ashman. 2016. A first test of the elemental allelopathy hypothesis for heterospecific pollen. American Journal of Botany doi: 10.3732/ajb.1500187

Stanley§, L., Forrester, N., Govindarajulu, R.,

Stanley§, L., Forrester, N., Govindarajulu, R., Liston, A., and T-L. Ashman. 2015. Geographic patterns of genetic variation in three genomes of North American diploid strawberries with special reference to Fragaria vesca subsp. bracteata.  Botany 93 (999): 1-16

Govindarajulu, R., M. Parks, Tennessen, J.A, Li

Govindarajulu, R., M. Parks, Tennessen, J.A, Liston A., and T-L. Ashman. 2015. Comparison of nuclear, plastid and mitochondrial phylogenies and the origin of wild octoploid strawberry species. American Journal of Botany 102 (4): 544-554

Meindl, G. A., and T-L. Ashman. 2015. Effects o

Meindl, G. A., and T-L. Ashman. 2015. Effects of floral metal accumulation on floral visitation, visitor richness and visitor composition: introducing the ‘elemental filter hypothesis’ American Journal of Botany 102:379-389

Koski, M., G. A. Meindl, G. Arceo-Gómez, M. Wol

Koski, M., G. A. Meindl, G. Arceo-Gómez, M. Wolowski, K. A. LeCroy and T-L. Ashman. 2015. Plant-flower visitor networks in a serpentine metacommunity: assessing traits associated with keystone plant species. Arthropod-Plant Interactions 9(1):9-21

Koski, M. and T-L. Ashman. 2015. Floral pigment

Koski, M. and T-L. Ashman. 2015. Floral pigmentation patterns provide first example of Gloger’s rule in plants. Nature Plants 1:4013  doi:10.1038/nplants.2014.13

Meindl, G. A., D. Bain and T-L. Ashman. 2014. V

Meindl, G. A., D. Bain and T-L. Ashman. 2014. Variation in nickel accumulation in leaves, reproductive organs and floral rewards in two hyperaccumulating Brassicaceae species. Plant and Soil 383 (1-2): 349-356

Tennessen, J.A., R. Govindarajulu, A. Liston an

Tennessen, J.A., R. Govindarajulu, A. Liston and T-L. Ashman. 2014. Evolutionary origins and dynamics of octoploid strawberry subgenomes revealed by dense targeted capture linkage maps. Genome Biology and Evolution  6(12):3295–3313

The Tree of Sex Consortium: T-L. Ashman, D. Bac

The Tree of Sex Consortium: T-L. Ashman, D. Bachtrog, H. Blackmon, E. E. Goldberg, M.W. Hahn, M. Kirkpatrick, J. Kitano, J. E. Mank, I. Mayrose, R. Ming, S.P. Otto , C. L. Peichel, M.W. Pennell, N. Perrin, L. Ross, N. Valenzuela, J.C. Vamosi. 2014. Tree of Sex: A database of sexual systems. Nature Scientific Data1:140015  DOI: 10.1038/sdata.2014.15

Meindl, G. A., D. Bain and T-L. Ashman. 2014. N

Meindl, G. A., D. Bain and T-L. Ashman. 2014. Nickel accumulation in leaves, floral organs and rewards varies by serpentine soil affinity. AoB Plants DOI: 10.1093/aobpla/plu036

Tree of Sex Consortium: D. Bachtrog, J. Mank, C

Tree of Sex Consortium: D. Bachtrog, J. Mank, C. Peichel, S. Otto, M. Kirkpatrick, T‐L. Ashman, M. Hahn, J. Kitano, I. Mayrose, R. Ming, N. Perrin, L. Ross, N. Valenzuela, and J. Vamosi. 2014. Sex Determination: Why so many ways of doing it? PLOS Biology  12(7): e1001899

Liston, A., R.C. Cronn and T-L. Ashman. 2014

Liston, A., R.C. Cronn and T-L. Ashman. 2014 Fragaria: a genus with deep historical roots and ripe for evolutionary and ecological insights.  Special issue on ‘Speaking of Food: Connecting basic and applied science’ to American Journal of Botany 101:1686-1699

Arceo-Gómez, G. and T-L. Ashman. 2014. Heterosp

Arceo-Gómez, G. and T-L. Ashman. 2014. Heterospecific pollen receipt effects self pollen more than outcross pollen: implications for mixed-mating plants.  Ecology 95(10), 2014: 2946–2952

Arceo-Gómez, G. and T-L. Ashman. 2014. Quantity

Arceo-Gómez, G. and T-L. Ashman. 2014. Quantity and quality of pollen limitation in Mimulus guttatus varies with flowering community diversity.  Oikos 123: 1261–1269

Meindl, G. A., and T-L. Ashman. 2014. Nickel ac

Meindl, G. A., and T-L. Ashman. 2014. Nickel accumulation by Streptanthus polygaloides (Brassicaceae) reduces floral visitation rate.  Journal of Chemical Ecology  40:128–135

Johnson, A.L., R. Govindarajulu, T-L. Ashman. 2

Johnson, A.L., R. Govindarajulu, T-L. Ashman. 2014. Bioclimatic evaluation of range in Fragaria (Rosaceae): consequences of variation in breeding system, ploidy and species age. Botanical Journal of the Linnaean Society  176:99-114

DeHart, K.S., G.A. Meindl, D. J. Bain, and T-L.

DeHart, K.S., G.A. Meindl, D. J. Bain, and T-L. Ashman. 2014. Elemental composition of serpentine plants depends on habitat specificity and organ type. Journal of Plant Nutrition and Soil Science  177 (6): 851-859

Wolowski, M., T-L. Ashman and L. Freitas. &nbsp

Wolowski, M., T-L. Ashman and L. Freitas.  2014. Meta-analysis of pollen limitation reveals the relevance of pollination generalization in the Atlantic forest of Brazil. PLoS ONE 9(2): e89498. doi:10.1371/journal.pone.0089498

Koski, M. and T-L. Ashman. 2014. Dissecting pol

Koski, M. and T-L. Ashman. 2014. Dissecting pollinator responses to a ubiquitous ultraviolet floral pattern in the wild. Functional Ecology 28 (4): 868-877

Arceo-Gómez, G. and T-L. Ashman. 2014. Coflower

Arceo-Gómez, G. and T-L. Ashman. 2014. Coflowering community context influences female fitness and alters the adaptive value of flower longevity in Mimulus guttatus. American Naturalist 183(2): E50-E63

Tennessen, J. A,  Govindarajulu, R., Listo

Tennessen, J. A,  Govindarajulu, R., Liston A., and T-L. Ashman. 2013. Targeted sequence capture provides insight into genome structure and genetics of male sterility in a gynodioecious diploid strawberry, Fragaria vesca ssp. bracteata (Rosaceae). Genes, Genomes and Genetics (G3) 3(8):1341-1351

Alonso, C., C. Navarro, G. Arc

Alonso, C., C. Navarro, G. Arceo-Gomez, Meindl, G. A., V. Parra-Tabla, and T-L Ashman. 2013. Among species differences in pollen quality and quantity limitation: implications for endemics in biodiverse hotspots. Annals of Botany 112(7):1461-1469

Ashman, T-L. A. Kwak, and B. Husband. 2013. Rev

Ashman, T-L. A. Kwak, and B. Husband. 2013. Revisiting the dioecy-polyploidy association: alternate pathways and research opportunities. Special Issue on ‘Trends in Polyploidy Research in Plants and Animals’ in Cytogenetic and Genome Research. 140:241-255

Koski, M., and T-L. Ashman. 2013.

Koski, M., and T-L. Ashman. 2013. Quantitative variation, heritability and correlations for floral ultraviolet traits in Argentina anserina (Rosaceae): implications for floral evolution in the UV spectrum. International Journal of Plant Sciences 174(8):1109-1120

Meindl, G. A., D.J. Bain, and T-L. Ashman. 2013

Meindl, G. A., D.J. Bain, and T-L. Ashman. 2013. Edaphic factors and plant-insect interactions: effects of serpentine soil on pollination and florivory. Oecologia 173:1355-1366

Dalton, R., M. Koski, and T-L. Ashman. 2013. Ma

Dalton, R., M. Koski, and T-L. Ashman. 2013. Maternal sex effects and inbreeding depression under varied environmental conditions in gynodioecious Fragaria vesca subsp. bracteata. Annals of Botany 112(3):613-21

Wolowski, M., C.F. Saad, T-L. Ashman and L. Fre

Wolowski, M., C.F. Saad, T-L. Ashman and L. Freitas. 2013. Predominance of self-compatibility in hummingbird-pollinated plants in the neotropics.  Naturwissenschaften 100:69-79.

 Meindl, G. A. and T-L. Ashman 2013. The e

 Meindl, G. A. and T-L. Ashman 2013. The effects of aluminum and nickel in nectar on the foraging behavior of bumblebees. Environmental Pollution 177:78-81.

Vamosi, J. C., J. A. Steets and T-L. Ashman. 20

Vamosi, J. C., J. A. Steets and T-L. Ashman. 2013 Drivers of pollen limitation: macroecological interactions between mating breeding system, rarity, and diversity.  Plant Ecology & Diversity 6(2):171-180

Salome, I. Govindarajulu, R., Falk, S., Parks,

Salome, I. Govindarajulu, R., Falk, S., Parks, M., Liston A., and T-L. Ashman. 2013. Ecological and phenotypic intermediacy and some geographic pattern to genetic admixture in natural hybrid of strawberry. American Journal of Botany 5:1-12.

Ashman, T-L. and G. Arceo-Gómez. 2013. Towards

Ashman, T-L. and G. Arceo-Gómez. 2013. Towards a predictive understanding of the effects of heterospecific pollen deposition.  Special Issue on ‘Mating Systems Evolution’ American Journal of Botany 100:1061-1070.

Govindarajulu, R., A. Liston and T-L. Ashman. 2

Govindarajulu, R., A. Liston and T-L. Ashman. 2013. Sex-determining chromosomes and sexual dimorphism: insights from genetic mapping of sex expression in a natural hybrid  Fragaria ×ananassa subsp. cuneifolia.  Heredity 110:430-438

Njuguna, W. A. Liston, R. Cron

Njuguna, W. A. Liston, R. Cronn, T-L. Ashman and N. Bassil. (2012) Phylogeny of Fragaria based on whole chloroplast genome sequencing. Molecular Phylogenetics and Evolution     http://dx.doi.org/10.1016/j.ympev.2012.08.026

Li, J. M. Koski, and T-L. Ashman. 2012. Functio

Li, J. M. Koski, and T-L. Ashman. 2012. Functional analysis of gynodioecy in Fragaria vesca ssp. bracteata.  Annals of Botany 109:545- 552. 

Otto, S.P.,  J. Pannell, C. L. Peichel, T-

Otto, S.P.,  J. Pannell, C. L. Peichel, T-L Ashman, D. Charlesworth, A. K. Chippendale, L. F. Delph, R. F. Guerrero, S. V. Scarpino and B. F. McAllister. (2011) About PAR: The distinct evolutionary dynamics of the Pseudoautosomal Region. Trends in Genetics 27(9):358-367

Alonso, C., C. M. Herrera, and T-L. Ashman. (20

Alonso, C., C. M. Herrera, and T-L. Ashman. (2012) A piece of the puzzle: A method for comparing pollination quality and quantity across multiple species and reproductive events. New Phytologist   193:532-542  

Gomez, G. A. and T-L. Ashman. (2011) Heterospec

Gomez, G. A. and T-L. Ashman. (2011) Heterospecific pollen deposition: Does diversity alter the consequences? New Phytologist 192(3): 738-746

Spigler, R. B. and T-L. Ashman. (2012) Gynodioe

Spigler, R. B. and T-L. Ashman. (2012) Gynodioecy to dioecy: Are we there yet? Special issue on 'Plant Mating' of Annals of Botany 109:531- 543

Burns, J.H., T.L. Ashman, J.A. Steets, A. Harmo

Burns, J.H., T.L. Ashman, J.A. Steets, A. Harmon-Threatt, and T.M. Knight (2011) A phylogenetically controlled analysis of the roles of reproductive traits in plant invasions. Oecologia : 166:1009-1017

Spigler, R.B., and T.L. Ashman (2011) Sex ratio and subdioecy in Fragaria virginiana: the roles o

Spigler, R.B., and T.L. Ashman (2011) Sex ratio and subdioecy in Fragaria virginiana: the roles of plasticity and gene flow examined. New Phytol : 190(4):158-168.

Shulaev, V., D.J. Sargent, R.N. Crowhurst, T.C. Mockler, O. Folkerts, A.L. Delcher, P. Jaiswal, K

Shulaev, V., D.J. Sargent, R.N. Crowhurst, T.C. Mockler, O. Folkerts, A.L. Delcher, P. Jaiswal, K. Mockaitis, A. Liston, S.P. Mane, P. Burns, T.M. Davis, J.P. Slovin, N. Bassil, R.P. Hellens, C. Evans, T. Harkins, C. Kodira, B. Desany, O.R. Crasta, R.V. Jensen, A.C. Allan, T.P. Michael, J.C. Setubal, J.M. Celton, D.J. Rees, K.P. Williams, S.H. Holt, J.J. Ruiz Rojas, M. Chatterjee, B. Liu, H. Silva, L. Meisel, A. Adato, S.A. Filichkin, M. Troggio, R. Viola, T.L. Ashman, H. Wang, P. Dharmawardhana, J. Elser, R. Raja, H.D. Priest, J.r. Bryant DW, S.E. Fox, S.A. Givan, L.J. Wilhelm, S. Naithani, A. Christoffels, D.Y. Salama, J. Carter, E. Lopez Girona, A. Zdepski, W. Wang, R.A. Kerstetter, W. Schwab, S.S. Korban, J. Davik, A. Monfort, B. Denoyes-Rothan, P. Arus, R. Mittler, B. Flinn, A. Aharoni, J.L. Bennetzen, S.L. Salzberg, A.W. Dickerman, R. Velasco, M. Borodovsky, R.E. Veilleux, and K.M... Folta (2011) The genome of woodland strawberry (Fragaria vesca). Nat Genet 43:109-116

Spigler, R.B., K.S. Lewers, and T.L. Ashman (2011) Genetic architecture of sexual dimorphism in a

Spigler, R.B., K.S. Lewers, and T.L. Ashman (2011) Genetic architecture of sexual dimorphism in a subdioecious plant with a proto-sex chromosome. Evolution 65:1114-1126

Collin, C.L., and T.-L. Ashman (2010) Root fungi in wild strawberry root colonization depends on

Collin, C.L., and T.-L. Ashman (2010) Root fungi in wild strawberry root colonization depends on host inbreeding. Evol Ecol Res 12:477-490

Goldberg, M.T., R.B. Spigler, and T.L. Ashman (2010) Comparative genetic mapping points to differ

Goldberg, M.T., R.B. Spigler, and T.L. Ashman (2010) Comparative genetic mapping points to different sex chromosomes in sibling species of wild strawberry (Fragaria). Genetics 186:1425-1433

Steets, J.A., and T.-L. Ashman (2010) Maternal effects of herbivory in Impatiens capensis

Steets, J.A., and T.-L. Ashman (2010) Maternal effects of herbivory in Impatiens capensis. Int. J. Plant Sci. 171(5):509-518.

Spigler, R.B., K.S. Lewers, A. Johnson, and T.-L. Ashman (2010) Comparative mapping reveals autos

Spigler, R.B., K.S. Lewers, A. Johnson, and T.-L. Ashman (2010) Comparative mapping reveals autosomal origin of sex chromosome in octoploid Fragaria virginiana. J. Heredity 101:S107-S117

Bishop, E., R.B. Spigler, and T.-L. Ashman (2010) Sex-allocation plasticity in hermaphrodites of

Bishop, E., R.B. Spigler, and T.-L. Ashman (2010) Sex-allocation plasticity in hermaphrodites of sexually dimorphic Fragaria virginiana (Rosaceae). Botany 88:231-240

Alonso, C., J. Vamosi, T.M. Knight, J. Steets, and T.-L. Ashman (2010) Is reproduction of endemic

Alonso, C., J. Vamosi, T.M. Knight, J. Steets, and T.-L. Ashman (2010) Is reproduction of endemic plant species particularly pollen limited in biodiversity hotspots? Oikos 119:1192-1200

Rohde, A.S., and T.-L. Ashman (2010) The effects of florivory and inbreeding on reproduction in h

Rohde, A.S., and T.-L. Ashman (2010) The effects of florivory and inbreeding on reproduction in hermaphrodites of the wild strawberry, Fragaria virginiana. Int. J. Plant Sci. 171:175-184

Case, A.L., and T.-L. Ashman (2009) Resources and pollinators contribute to population sex ratio

Case, A.L., and T.-L. Ashman (2009) Resources and pollinators contribute to population sex ratio bias and pollen limitation in gynodioecious wild strawberry (Fragaria virginiana). Oikos 118:1250-1260

Burd, M., T.-L. Ashman, D.R. Campbell, M.R. Dudash, M.O. Johnson, T.M. Knight, S.J. Mazer, R.J. M

Burd, M., T.-L. Ashman, D.R. Campbell, M.R. Dudash, M.O. Johnson, T.M. Knight, S.J. Mazer, R.J. Mitchell, J.A. Steets, and J.C. Vamosi (2009) Ovule number per flower in a world of unpredictable pollination. Am. J. Bot. 96:1159-1167

Ashman, T.-L. (2009) Sniffing out patterns of sexual dimorphism in floral scent. Functional E

Ashman, T.-L. (2009) Sniffing out patterns of sexual dimorphism in floral scent. Functional Ecol. 23:852-862

Majetic, C.J., R. Raguso, and T.-L. Ashman (2009) The sweet smell of success: Floral scent affect

Majetic, C.J., R. Raguso, and T.-L. Ashman (2009) The sweet smell of success: Floral scent affects pollinator attraction and seed fitness in Hesperis matronalis (Brassicaceae). Func. Ecol. 3:480-487
Dr. Ashman received her Ph.D. in 1991 with M.L. Stanton at the University of California at Davis, performed her postdoctoral studies with DJ Schoen at McGill University, and joined the Department in 1994.