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

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.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:121

Enthalten in:

Proceedings of the National Academy of Sciences of the United States of America - 121(2024), 10 vom: 05. März, Seite e2305228121

Sprache:

Englisch

Beteiligte Personen:

Karimi, Nisa [VerfasserIn]
Krieg, Christopher P [VerfasserIn]
Spalink, Daniel [VerfasserIn]
Lemmon, Alan R [VerfasserIn]
Lemmon, Emily Moriarty [VerfasserIn]
Eifler, Evan [VerfasserIn]
Hernández, Adriana I [VerfasserIn]
Chan, Patricia W [VerfasserIn]
Rodríguez, Aarón [VerfasserIn]
Landis, Jacob B [VerfasserIn]
Strickler, Susan R [VerfasserIn]
Specht, Chelsea D [VerfasserIn]
Givnish, Thomas J [VerfasserIn]

Links:

Volltext

Themen:

California Floristic Province
Diversification
Environmental heterogeneity
Historical biogeography
Journal Article
Phylogenomics

Anmerkungen:

Date Completed 26.02.2024

Date Revised 14.03.2024

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1073/pnas.2305228121

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM368842010