Paper · 2001 · Evolution

SPATIAL POPULATION GENETIC STRUCTURE IN TRILLIUM GRANDIFLORUM: THE ROLES OF DISPERSAL, MATING, HISTORY, AND SELECTION

Susan Kalisz; John D. Nason; Frances M. Hanzawa; et al.

10
claims
20
verbatim quotes
15
citations
1
research areas
—
Not open access

Abstract

The roles of the various potential ecological and evolutionary causes of spatial population genetic structure (SPGS) cannot in general be inferred from the extant structure alone. However, a stage-specific analysis can provide clues as to the causes of SPGS. We conducted a stage-specific SPGS analysis of a mapped population of about 2000 Trillium grandiflorum (Liliaceae), a long-lived perennial herb. We compared SPGS for juvenile (J), nonreproductive (NR), and reproductive (R) stages. Fisher's exact test showed that genotypes had Hardy-Weinberg frequencies at all loci and stage classes. Allele frequencies did not differ between stages. Bootstrapped 99% confidence intervals (99%CI) indicate that F-statistic values are indistinguishable from zero, (except for a slightly negative FIT for the R stage). Spatial autocorrelation was used to calculate f, the average kinship coefficient between individuals within distance intervals. Null hypothesis 99%CIs for f were constructed by repeatedly randomizing genotypic locations. Significant positive fine-scale genetic structure was detected in the R and NR stages, but not in the J stage. This structure was most pronounced in the R stage, and declined by about half in each remaining stage: near-neighbor f = 0.122, 0.065, 0.027, for R, NR, and J, respectively. For R and NR, the near-neighbor f lies outside the null hypothesis 99%CI, indicating kinship at approximately the level of half-sibs and first cousins, respectively. We also simulated the expected SPGS of juveniles post dispersal, based on measured R-stage SPGS, the mating system, and measured pollen and seed dispersal properties. This provides a null hypothesis expectation (as a 99%CI) for the J-stage correlogram, against which to test the likelihood that post-dispersal events have influenced J-stage SPGS. The actual J correlogram lies within the null hypothesis 99%CI for the shortest distance interval and nearly all other distance intervals indicating that the observed low recruitment, random mating and seed dispersal patterns are sufficient to account for the disappearance of SPSG between the R and the J stages. The observed increase in SPGS between J and R stages has two potential explanations: history and local selection. The observed low total allelic diversity is consistent with a past bottleneck: a possible historical explanation. Only a longitudinal stage-specific study of SPGS structure can distinguish between historical events and local selection as causes of increased structure with increasing life history stage.Corresponding Editor: O. Savolainen

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Claims 10

Observationobservedoriginal resultmeasured

Claim · model-written summary

Genotypes had Hardy-Weinberg frequencies at all loci and stage classes.

Taxon
TRILLIUM GRANDIFLORUMTrillium grandiflorumt0
Outcome
Hardy-Weinberg frequenciese0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Trillium grandiflorum
Trillium grandiflorum · TaxonPaul Johnston · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“genotypes had Hardy-Weinberg frequencies at all loci and stage classes”

✓ located verbatim in the source · abstract, characters 522–592 · show in text ↑
t0

“TRILLIUM GRANDIFLORUM”

✓ located verbatim in the source · title, characters 40–61 · show in text ↑
Associationobservedoriginal resultno effectmeasured

Claim · model-written summary

Allele frequencies did not differ between stages.

Taxon
TRILLIUM GRANDIFLORUMTrillium grandiflorumt0
Organ / stage
stagese0
Outcome
Allele frequenciese0
Direction
did not differe0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Trillium grandiflorum
Trillium grandiflorum · TaxonPaul Johnston · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“Allele frequencies did not differ between stages”

✓ located verbatim in the source · abstract, characters 594–642 · show in text ↑
t0

“TRILLIUM GRANDIFLORUM”

✓ located verbatim in the source · title, characters 40–61 · show in text ↑
Observationobservedoriginal resultmeasured

Claim · model-written summary

F-statistic values were indistinguishable from zero except for slightly negative FIT in reproductive plants.

Taxon
TRILLIUM GRANDIFLORUMTrillium grandiflorumt0
Outcome
F-statistic valuese0
Qualifier
except for a slightly negative FIT for the R stagee0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Trillium grandiflorum
Trillium grandiflorum · TaxonPaul Johnston · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“F-statistic values are indistinguishable from zero, (except for a slightly negative FIT for the R stage)”

✓ located verbatim in the source · abstract, characters 704–808 · show in text ↑
t0

“TRILLIUM GRANDIFLORUM”

✓ located verbatim in the source · title, characters 40–61 · show in text ↑
Associationobservedoriginal resultpositivesignificant (as stated)measured

Claim · model-written summary

Positive fine-scale genetic structure was detected in reproductive and nonreproductive stages but not juvenile plants.

Taxon
TRILLIUM GRANDIFLORUMTrillium grandiflorumt0
Organ / stage
R and NR stagese0
Outcome
fine-scale genetic structuree0
Direction
positivee0
Qualifier
but not in the J stagee0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Trillium grandiflorum
Trillium grandiflorum · TaxonPaul Johnston · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“Significant positive fine-scale genetic structure was detected in the R and NR stages, but not in the J stage”

✓ located verbatim in the source · abstract, characters 1031–1140 · show in text ↑
t0

“TRILLIUM GRANDIFLORUM”

✓ located verbatim in the source · title, characters 40–61 · show in text ↑
Observationobservedoriginal resultmeasured

Claim · model-written summary

Near-neighbor kinship coefficient was 0.122 in reproductive plants.

Taxon
TRILLIUM GRANDIFLORUMTrillium grandiflorumt0
Organ / stage
Re0
Outcome
near-neighbor fe0
Value
0.122e0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Trillium grandiflorum
Trillium grandiflorum · TaxonPaul Johnston · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“near-neighbor f = 0.122, 0.065, 0.027, for R, NR, and J, respectively”

✓ located verbatim in the source · abstract, characters 1245–1314 · show in text ↑
t0

“TRILLIUM GRANDIFLORUM”

✓ located verbatim in the source · title, characters 40–61 · show in text ↑
Observationobservedoriginal resultmeasured

Claim · model-written summary

Near-neighbor kinship coefficient was 0.065 in nonreproductive plants.

Taxon
TRILLIUM GRANDIFLORUMTrillium grandiflorumt0
Organ / stage
NRe0
Outcome
near-neighbor fe0
Value
0.065e0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Trillium grandiflorum
Trillium grandiflorum · TaxonPaul Johnston · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“near-neighbor f = 0.122, 0.065, 0.027, for R, NR, and J, respectively”

✓ located verbatim in the source · abstract, characters 1245–1314 · show in text ↑
t0

“TRILLIUM GRANDIFLORUM”

✓ located verbatim in the source · title, characters 40–61 · show in text ↑
Observationobservedoriginal resultmeasured

Claim · model-written summary

Near-neighbor kinship coefficient was 0.027 in juvenile plants.

Taxon
TRILLIUM GRANDIFLORUMTrillium grandiflorumt0
Organ / stage
Je0
Outcome
near-neighbor fe0
Value
0.027e0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Trillium grandiflorum
Trillium grandiflorum · TaxonPaul Johnston · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“near-neighbor f = 0.122, 0.065, 0.027, for R, NR, and J, respectively”

✓ located verbatim in the source · abstract, characters 1245–1314 · show in text ↑
t0

“TRILLIUM GRANDIFLORUM”

✓ located verbatim in the source · title, characters 40–61 · show in text ↑
Associationobservedoriginal resultmeasured

Claim · model-written summary

The juvenile correlogram fell within simulated null intervals at the shortest and almost all other distances.

Taxon
TRILLIUM GRANDIFLORUMTrillium grandiflorumt0
Outcome
J correlograme0
Qualifier
shortest distance interval and nearly all other distance intervalse0
Comparator
null hypothesis 99%CIe0

Not reportedDirection

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Trillium grandiflorum
Trillium grandiflorum · TaxonPaul Johnston · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“The actual J correlogram lies within the null hypothesis 99%CI for the shortest distance interval and nearly all other distance intervals”

✓ located verbatim in the source · abstract, characters 1829–1966 · show in text ↑
t0

“TRILLIUM GRANDIFLORUM”

✓ located verbatim in the source · title, characters 40–61 · show in text ↑
Mechanismauthor interpretationoriginal resultmeasured

Claim · model-written summary

Low recruitment, random mating and seed dispersal were sufficient to account for loss of spatial structure between reproductive and juvenile stages.

Taxon
TRILLIUM GRANDIFLORUMTrillium grandiflorumt0
Outcome
disappearance of SPSGe0
Qualifier
low recruitment, random mating and seed dispersal patternse0

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Trillium grandiflorum
Trillium grandiflorum · TaxonPaul Johnston · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“the observed low recruitment, random mating and seed dispersal patterns are sufficient to account for the disappearance of SPSG between the R and the J stages”

✓ located verbatim in the source · abstract, characters 1983–2141 · show in text ↑
t0

“TRILLIUM GRANDIFLORUM”

✓ located verbatim in the source · title, characters 40–61 · show in text ↑
Associationauthor interpretationoriginal resultmeasured

Claim · model-written summary

Low total allelic diversity was consistent with a past bottleneck.

Taxon
TRILLIUM GRANDIFLORUMTrillium grandiflorumt0
Outcome
low total allelic diversitye0
Qualifier
past bottlenecke0
Comparator
past bottlenecke0

Not reportedDirection

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Trillium grandiflorum
Trillium grandiflorum · TaxonPaul Johnston · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“The observed low total allelic diversity is consistent with a past bottleneck”

✓ located verbatim in the source · abstract, characters 2257–2334 · show in text ↑
t0

“TRILLIUM GRANDIFLORUM”

✓ located verbatim in the source · title, characters 40–61 · show in text ↑