Genetic variation and population structure of the mixed-mating cactus, Melocactus curvispinus (Cactaceae)

Nassar, Jafet M.; Hamrick, J. L.; Fleming, Theodore H.

doi:10.1046/j.1365-2540.2001.00910.x

Cited by 32 publications

(54 citation statements)

References 37 publications

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“…Although a formal pollinator exclusion experiment is needed to infer the relative importance of sphingids versus honeybees, the available evidence suggests that sphingids are the major pollinators of Sonoran populations of S. gummosus. Levels of genetic variation in populations of S. gummosus are within the range or slightly greater than that observed for other columnar cacti (Table 2, Nassar et al, 2001;Hamrick et al, 2002). However, in contrast to other columnar cacti present on both sides of the gulf , mainland populations of S. gummosus exhibit slightly greater levels of genetic variation than peninsular populations.…”

Section: Discussionmentioning

confidence: 61%

The genetic structure of a columnar cactus with a disjunct distribution: Stenocereus gummosus in the Sonoran desert

Clark‐Tapia

Molina‐Freaner

2003

Heredity

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Stenocereus gummosus is a columnar cactus endemic to the Sonoran desert that exhibits a disjunct distribution: it is widely distributed in Baja California and restricted to a small coastal area in mainland Sonora. In this paper, we examine the genetic structure and the mating system of this species in order to explore the origin of the disjunction and describe aspects of the pollination biology. Flowers are nocturnal, pollinated mainly by sphingids and self-incompatible. Polymorphism for allozymes (11 loci) was relatively high (P ¼ 75%) but moderate levels of heterozygosity were detected (H o ¼ 0.103 and H e ¼ 0.261). Sonoran populations exhibited higher levels of genetic variation than peninsular populations. H e declined with latitude when just peninsular and two island populations are included. Substantial levels of inbreeding within populations (f ¼ 0.60), moderate differentiation among populations (y ¼ 0.10), and no evidence of isolation by distance were detected. The neighbor-joining phenogram showed Sonoran and island populations nested within peninsular populations. Mainland populations showed greater genetic similarity to island populations, supporting a dispersal hypothesis for the origin of the disjunction. Future studies using DNA markers are suggested in order to better understand the forces that have shaped the genetic structure of this species.

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Section: Discussionmentioning

confidence: 61%

The genetic structure of a columnar cactus with a disjunct distribution: Stenocereus gummosus in the Sonoran desert

Clark‐Tapia

Molina‐Freaner

2003

Heredity

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“…Total genetic diversity (H T ), genetic diversity within (H s ) and among (D ST ) populations, and genetic differentiation coefficient (G ST ), Wright's parameter of differentiation among subpopulations (F ST ), and parameters estimating gene flow (Nm (GST) and Nm (FST) ), for wild, managed in situ, and all studied populations (All) of Escontria chiotilla. A = 3, H e = 0.25) and by Nassar et al (2001) for Melocactus curvis-pinus (P = 89.5%, A = 3.53, H e = 0.145). Nevertheless, it is important to consider that only five of the loci analysed were polymorphic, and that further analyses including more polymorphic loci could help to further refine the present information.…”

Section: Discussionmentioning

confidence: 90%

Population Genetics of Escontria chiotilla in Wild and Silvicultural Managed Populations in the Tehuacán Valley, Central Mexico

Tinoco

Casas

Luna

et al. 2005

Genet Resour Crop Evol

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Escontria chiotilla is a columnar cactus that grows in the arid and semiarid lands of Central Mexico and produces edible fruit with economic. In the wild, this plant species is distributed as part of thorn-scrub and tropical deciduous forests, but in the Tehuaca´n Valley also occurs in silvicultural managed in situ populations, in which people practise artificial selection enhancing phenotypes with larger fruits. The population genetics of wild and managed populations was studied to analyse the effects of management on genetic structure of E. chiotilla. A total of 150 individuals from six populations were studied, analysing 13 loci for eight enzymes by starch gel electrophoresis. The genetic variation in wild populations was significantly higher than in managed populations (H o = 0.079, H e = 0.134, H T = 0.370, and H o = 0.052, H e = 0.110, H T = 0.298, respectively), indicating that silvicultural management has caused a reduction of the genetic variation in populations. Most of the genetic variation in both wild and managed populations occurs within populations (D ST = 0.027 in the wild and 0.018 in managed populations). The genetic distance coefficients were slightly different for silvicultural managed populations than in wild ones, illustrating an incipient effect of management on the genetic structure of populations. However, values of Nm GST = 3.845 and Nm FST = 3.848 indicate that a high gene flow counteracts the effects of human selection on the differentiation of populations.

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“…Small F st values have been justified as a result of long-distance pollen dispersal that has a homogenizing influence at the regional level (OteroArnaiz et al 2005). Limited pollen movement and seed dispersal may contribute to an increase in genetic substructuring within populations (Nassar et al 2001). Cactus species of the genus Lophocereus, pollinated by moths (Upiga vireceus), have been described as highly structured (F st = 0.352; Nason et al 2002).…”

Section: Discussionmentioning

confidence: 99%

Esterase Polymorphism and the Analysis of Genetic Diversity and Structure in Cactus Populations Descended from Cereus peruvianus Plants Regenerated In Vitro

et al. 2011

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The genetic structure of Cereus peruvianus populations descended from cultivated plants (F(1) populations) and from plants regenerated in vitro (R(1) populations) was analyzed using α- and β-esterase isozymes in native PAGE. The estimated proportion of polymorphic loci was higher (50%) in the R(1) populations than the F(1) populations (42.85%). The mean observed (0.5599) and expected (0.5620) heterozygosity in R(1) descendents was also higher than the rates in F(1) descendents (H (o) = 0.4142; H (e) = 0.4977). A low level of population differentiation was detected in R(1) descendents (F (st) = 0.05). In contrast, population differentiation was high in F(1) descendents (0.2583). Esterase analysis using PAGE showed that artificial selection by silvicultural management provides high genetic diversity and a large genetic basis for C. peruvianus, whereas in vitro selection from callus tissue culture involves an increase of heterozygosity levels in descendents from somaclones and a low level of interpopulational divergence.

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Genetic variation and population structure of the mixed-mating cactus, Melocactus curvispinus (Cactaceae)

Cited by 32 publications

References 37 publications

The genetic structure of a columnar cactus with a disjunct distribution: Stenocereus gummosus in the Sonoran desert

The genetic structure of a columnar cactus with a disjunct distribution: Stenocereus gummosus in the Sonoran desert

Population Genetics of Escontria chiotilla in Wild and Silvicultural Managed Populations in the Tehuacán Valley, Central Mexico

Esterase Polymorphism and the Analysis of Genetic Diversity and Structure in Cactus Populations Descended from Cereus peruvianus Plants Regenerated In Vitro

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