Published August 14, 2023 | Version v1
Software Open

Data from: A few essential genetic loci distinguish Penstemon species with flowers adapted to pollination by bees or hummingbirds

  • 1. University of South Carolina

Description

In the formation of species, adaptation by natural selection generates distinct combinations of traits that function well together. The maintenance of adaptive trait combinations in the face of gene flow depends on the strength and nature of selection acting on the underlying genetic loci. Floral pollination syndromes exemplify the evolution of trait combinations adaptive for particular pollinators. The North American wildflower genus Penstemon displays remarkable floral syndrome convergence, with at least 20 separate lineages that have evolved from ancestral bee pollination syndrome (wide blue-purple flowers that present a landing platform for bees and small amounts of nectar) to hummingbird pollination syndrome (bright red narrowly tubular flowers offering copious nectar). Related taxa that differ in floral syndrome offer an attractive opportunity to examine the genomic basis of complex trait divergence. In this study, we characterized genomic divergence among 229 individuals from a Penstemon species complex that includes both bee and hummingbird floral syndromes. Field plants are easily classified into species based on phenotypic differences and hybrids displaying intermediate floral syndromes are rare. Despite unambiguous phenotypic differences, genomewide differentiation between species is minimal. Hummingbird-adapted populations are more genetically similar to nearby bee-adapted populations than to geographically distant hummingbird-adapted populations, in terms of genomewide dXY. However, a small number of genetic loci are strongly differentiated between species. These ~ 20 "species-diagnostic loci", which appear to have nearly fixed differences between pollination syndromes, are sprinkled throughout the genome in high recombination regions. Several map closely to previously established floral trait QTLs. The striking difference between the diagnostic loci and the genome as whole suggests strong selection to maintain distinct combinations of traits, but with sufficient gene flow to homogenize the genomic background. A surprisingly small number of alleles confer phenotypic differences that form the basis of species identity in this species complex.

Notes

Funding provided by: National Institute of General Medical Sciences
Crossref Funder Registry ID: http://dx.doi.org/10.13039/100000057
Award Number: R35GM142636

Files

README.md

Files (75.8 kB)

Name Size Download all
md5:0cf3fc25f2139d5473959878c5be2570
40.3 kB Preview Download
md5:bee7e0eff40b39f32e7c3c2b4f950875
35.5 kB Preview Download

Additional details

Related works

Is source of
10.5061/dryad.xpnvx0kmp (DOI)