Abstract
Although genome size (GS) is decoupled from organismal complexity, a phenomenon known as the C-value paradox, some authors have proposed that GS may play an adaptive role when correlated with ecologically relevant traits. Among diploid Coffea, GS variation is modest but measurable, offering an opportunity to test this hypothesis. Using a well-resolved phylogeny and phylogenetic comparative methods, we evaluated whether GS is phylogenetically correlated with ecological traits including latitudinal range, elevational distribution, thermal tolerance, and caffeine content (CAF). GS showed substantial phylogenetic signal and correlated positively with CAF, but no phylogenetic association was detected with the other variables. Notably, this association traces to a single, lineage-specific shift at the base of a clade comprising the species with the largest genomes and highest CAF, occurring in West and Central Africa. Comparisons between two sequenced genomes, Coffea canephora and C. eugenioides, which differ in caffeine production, revealed that gene copy number does not correlate with CAF levels, suggesting that increases in caffeine production are more likely driven by regulatory changerather than gene duplication. Overall, these findings do not support a generalized adaptive model for GS evolution in Coffea, but instead indicate that the observed associations reflect lineage-specific historical events rather than direct adaptive responses.
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Claims 8
Claim · model-written summary
Genome size in diploid Coffea showed substantial phylogenetic signal.
CoffeaOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Among diploid Coffea, GS variation is modest but measurable”
e1“GS showed substantial phylogenetic signal and correlated positively with CAF”
Claim · model-written summary
Genome size correlated positively with caffeine content (CAF) across diploid Coffea.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Among diploid Coffea, GS variation is modest but measurable”
e1“GS showed substantial phylogenetic signal and correlated positively with CAF”
e7“latitudinal range, elevational distribution, thermal tolerance, and caffeine content (CAF)”
Claim · model-written summary
Genome size showed no phylogenetic association with latitudinal range, elevational distribution or thermal tolerance.
- Outcome
- phylogenetic associatione2
- Direction
- no_changeinferrede2
- Comparator
- latitudinal range, elevational distribution, thermal tolerancee7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Among diploid Coffea, GS variation is modest but measurable”
e2“no phylogenetic association was detected with the other variables”
e7“latitudinal range, elevational distribution, thermal tolerance, and caffeine content (CAF)”
Claim · model-written summary
The genome size and caffeine association traces to a single lineage-specific shift at the base of the clade with the largest genomes and highest CAF, in West and Central Africa.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Among diploid Coffea, GS variation is modest but measurable”
e3“this association traces to a single, lineage-specific shift at the base of a clade comprising the species with the largest genomes and highest CAF, occurring in West and Central Africa”
Claim · model-written summary
Gene copy number does not correlate with CAF levels in Coffea canephora or C. eugenioides.
- Taxon
- Coffea canephora and C. eugenioidesCoffea eugenioides
Coffea canephorae5 - Gene
- gene copy numbere4
- Outcome
- CAF levelse4
- Direction
- no_changeinferrede4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“gene copy number does not correlate with CAF levels”
e5“Comparisons between two sequenced genomes, Coffea canephora and C. eugenioides, which differ in caffeine production”
Claim · model-written summary
Increases in caffeine production are more likely driven by regulatory change than by gene duplication in Coffea.
- Outcome
- Increases in caffeine productione6
- Qualifier
- more likely driven by regulatory changerather than gene duplicatione6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Among diploid Coffea, GS variation is modest but measurable”
e6“increases in caffeine production are more likely driven by regulatory changerather than gene duplication”
Claim · model-written summary
The data do not support a generalized adaptive model for genome size evolution in Coffea.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Among diploid Coffea, GS variation is modest but measurable”
e7“these findings do not support a generalized adaptive model for GS evolution in Coffea”
Claim · model-written summary
The observed associations reflect lineage-specific historical events rather than direct adaptive responses.
- Outcome
- observed associationse6
- Qualifier
- lineage-specific historical events rather than direct adaptive responsese6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Among diploid Coffea, GS variation is modest but measurable”
e6“the observed associations reflect lineage-specific historical events rather than direct adaptive responses”