Chromosomal evolution, environmental heterogeneity, and migration drive spatial patterns of species richness in Calochortus (Liliaceae).

Autor:	Karimi N; Science and Conservation Division, Missouri Botanical Garden, St. Louis, MO 63110.; Department of Botany, University of Wisconsin-Madison, Madison, WI 53706., Krieg CP; Department of Botany, University of Wisconsin-Madison, Madison, WI 53706., Spalink D; Department of Ecology and Conservation Biology, Texas A&M University, College Station, TX 77845., Lemmon AR; Department of Scientific Computing, Florida State University, Tallahassee, FL 32306., Lemmon EM; Department of Biological Science, Florida State University, Tallahassee, FL 32306., Eifler E; Department of Botany, University of Wisconsin-Madison, Madison, WI 53706., Hernández AI; School of Integrative Plant Science, Cornell University, Ithaca, NY 14853.; L. H. Bailey Hortorium, Cornell University, Ithaca, NY 14853., Chan PW; Department of Botany, University of Wisconsin-Madison, Madison, WI 53706., Rodríguez A; Departamento de Botánica y Zoología, Universidad de la Guadalajara, Zapopan, Jalisco 45200, Mexico., Landis JB; School of Integrative Plant Science, Cornell University, Ithaca, NY 14853.; Departamento de Botánica y Zoología, Universidad de la Guadalajara, Zapopan, Jalisco 45200, Mexico.; Boyce Thompson Institute for Plant Research, Ithaca, NY 14853., Strickler SR; Boyce Thompson Institute for Plant Research, Ithaca, NY 14853., Specht CD; School of Integrative Plant Science, Cornell University, Ithaca, NY 14853.; L. H. Bailey Hortorium, Cornell University, Ithaca, NY 14853., Givnish TJ; Department of Botany, University of Wisconsin-Madison, Madison, WI 53706.
Jazyk:	angličtina
Zdroj:	Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2024 Mar 05; Vol. 121 (10), pp. e2305228121. Date of Electronic Publication: 2024 Feb 23.
DOI:	10.1073/pnas.2305228121
Abstrakt:	We used nuclear genomic data and statistical models to evaluate the ecological and evolutionary processes shaping spatial variation in species richness in Calochortus (Liliaceae, 74 spp.). Calochortus occupies diverse habitats in the western United States and Mexico and has a center of diversity in the California Floristic Province, marked by multiple orogenies, winter rainfall, and highly divergent climates and substrates (including serpentine). We used sequences of 294 low-copy nuclear loci to produce a time-calibrated phylogeny, estimate historical biogeography, and test hypotheses regarding drivers of present-day spatial patterns in species number. Speciation and species coexistence require reproductive isolation and ecological divergence, so we examined the roles of chromosome number, environmental heterogeneity, and migration in shaping local species richness. Six major clades-inhabiting different geographic/climatic areas, and often marked by different base chromosome numbers (n = 6 to 10)-began diverging from each other ~10.3 Mya. As predicted, local species number increased significantly with local heterogeneity in chromosome number, elevation, soil characteristics, and serpentine presence. Species richness is greatest in the Transverse/Peninsular Ranges where clades with different chromosome numbers overlap, topographic complexity provides diverse conditions over short distances, and several physiographic provinces meet allowing immigration by several clades. Recently diverged sister-species pairs generally have peri-patric distributions, and maximum geographic overlap between species increases over the first million years since divergence, suggesting that chromosomal evolution, genetic divergence leading to gametic isolation or hybrid inviability/sterility, and/or ecological divergence over small spatial scales may permit species co-occurrence. Competing Interests: Competing interests statement:The authors declare no competing interest.
Databáze:	MEDLINE
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