Search bioRxiv⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/2024.10.22.619585

The population structure of invasive Lantana camara is shaped by its mating system

Praveen, P.·Gopal, R.·Ramakrishnan, U.
View original source ↗Export metadata ↓

Abstract

Over the last century, invasive species have emerged as an important driver of global biodiversity loss. Many invasive species have low genetic diversity in the invaded habitats, owing to the demographic bottleneck during introduction. Lantana camara is one of the hundred most problematic invasive species globally. Despite its ecological importance in many countries, our understanding of the genetic diversity patterns of this plant remains poor. Previous studies hypothesize that invasive L. camara is a species complex with a hybrid origin, though this has never been tested. We investigated the population genetic patterns of L. camara by sampling 359 plants that represented a spectrum of flower colour variants across 36 locations, spanning most of the biogeographic regions across India. Analyses of the population structure using 19,008 SNPs revealed that L. camara in India exhibits a strong genetic structure. Interestingly, the structuring pattern does not exhibit a strong correlation with geography. In the structure analysis, individuals with similar flower colours clustered together regardless of their location of origin. The genetic distance between most of the individuals was low, indicating the absence of multiple species. A high inbreeding coefficient and a low proportion of heterozygous sites observed suggested that the strong structure could be due to self-fertilization. This was further confirmed by bagging experiments, which demonstrated that L. camara is self-compatible in India. Thus, we infer that L. camara exists as homozygous inbred lines formed by self-fertilization and that these inbred lines could be associated with distinct flower colours. Together, this would explain the correlation between flower colour and genetic structure, and the lack of geographic structure. These results refute the argument that L. camara is a species complex and emphasize the importance of the mating system in shaping the patterns of diversity in this invasive species. Our findings highlight a hitherto unknown role for mating systems in invasive species, furthering our understanding of evolution in invasive species.

Source connections

Explore related subjects

evolutionary biologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Praveen, P., Gopal, R., Ramakrishnan, U.. 2024-10-25. The population structure of invasive Lantana camara is shaped by its mating system. https://doi.org/10.1101/2024.10.22.619585

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

RELAX does not reproduce its own estimates at default settings, and its output does not show it

Selection-intensity estimates from RELAX are reported as a point value of K with a likelihood-ratio P. We report that, at default settings and on data of ordinary size, the program does not reproduce its own fits. Of 27 enzyme entries refitted under two optimiser configurations, none reproduced its log-likelihood to within 0.01 units; the median change was 103 units, the largest over 3,400, and four verdicts reversed. Eighty null orthologues reproduced none. A byte-identical command returned a distinct likelihood on every repetition, single-threaded, across three releases, and on alignments simulated under the fitted model, where 3.3 per cent of replicates reproduced. The documented random-number seed never reaches the generator when assigned on the command line, yet reads back as the value supplied. PAML localises the cause: its two-ratio model, without site classes, reproduced its log-likelihood for all 288 genes; its site-class models agreed for 27 to 67 per cent. The instability follows the mixture over sites, not the program. The output does not show it: 46 of 410 fits ended with a negative likelihood-ratio statistic, impossible under convergence, and 123 of 410 report a K re-estimated under a domain restriction rather than the unconstrained maximum. Of 234 published studies using RELAX, none reported a seed. Seeding while holding the thread count at one reproduced sixty of sixty runs on twenty genes under two releases; the seed alone reproduced none of five, and no documentation states the second condition. We recommend that fits be repeated and their dispersion published.

evolutionary biology↗
bioRxiv2026

Sequential accumulation of adaptive alleles forms an inversion supergene in deer mice

Supergenes are clusters of co-inherited loci that affect multiple or complex phenotypes. Despite the growing number of chromosomal inversions identified as supergenes in natural populations, their molecular basis and evolutionary history often remain obscure. Here, we identified two candidate genes, Slc45a2 and Npr3, within a 41-Mb inversion supergene in the deer mouse (Peromyscus maniculatus) that respectively drive darker coats and longer tails - two traits associated with forest adaptation. Mice homozygous for the inversion (inv/inv) exhibit elevated Slc45a2 expression in melanocytes relative to the congenic standard genotype (std/std), disrupting pheomelanin production. In parallel, downregulation of Npr3 in inv/inv mouse growth plates prolongs postnatal growth of caudal vertebrae, resulting in tail elongation. Population-level analyses further implicate that this supergene arose through the subsequent accumulation of the Npr3 allele within the inversion, rather than by capturing all beneficial mutations at its origin.

evolutionary biology↗
bioRxiv2026

Toxin structure shapes palatability in a chemically defended butterfly

The toxicity of chemical defences is well studied, but the potential contribution of compound structure to predator deterrence remains largely unexplored. Whether predation acts more strongly on toxicity or unpalatability remains largely untested, partly because few systems allow toxin structure to vary independently of quantity. Heliconius sara larvae provide such a system: those reared on Passiflora auriculata sequester cyclopentenyl cyanogenic glucosides (CGs), while those reared on P. biflora biosynthesise comparable quantities of aliphatic CGs. Using two invertebrate predators, Camponotus floridanus ants and Hierodula membranacea mantids, we tested whether this structural difference affects palatability independent of toxicity. Mantids rejected larvae with cyclopentenyl CGs more often than larvae with aliphatic CGs, despite no detectable difference in total CG content. This pattern was mirrored in extract-based assays with ants, independently of cyanide release: extracts with cyclopentenyl CGs remained deterrent, while extracts with aliphatic CGs did not differ in deterrence from water. Live larvae, by contrast, elicited similar responses from ants regardless of CG structure. These results show that variation in toxin structure can strongly affect palatability, with some compounds conferring greater protection than others. This demonstrates the importance of chemical structural diversity in the evolution of chemical defences.

evolutionary biology↗