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Francisco Molina-freaner - One of the best experts on this subject based on the ideXlab platform.
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The genetic structure of a columnar cactus with a Disjunct Distribution: Stenocereus gummosus in the Sonoran desert.
Heredity, 2003Co-Authors: Ricardo Clark-tapia, Francisco Molina-freanerAbstract:The genetic structure of a columnar cactus with a Disjunct Distribution: Stenocereus gummosus in the Sonoran desert
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The genetic structure of a columnar cactus with a Disjunct Distribution: Stenocereus gummosus in the Sonoran desert.
Heredity, 2003Co-Authors: Ricardo Clark-tapia, Francisco Molina-freanerAbstract: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=75%) but moderate levels of heterozygosity were detected (H(o)=0.103 and H(e)=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=0.60), moderate differentiation among populations (theta=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.
Ricardo Clark-tapia - One of the best experts on this subject based on the ideXlab platform.
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The genetic structure of a columnar cactus with a Disjunct Distribution: Stenocereus gummosus in the Sonoran desert.
Heredity, 2003Co-Authors: Ricardo Clark-tapia, Francisco Molina-freanerAbstract:The genetic structure of a columnar cactus with a Disjunct Distribution: Stenocereus gummosus in the Sonoran desert
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The genetic structure of a columnar cactus with a Disjunct Distribution: Stenocereus gummosus in the Sonoran desert.
Heredity, 2003Co-Authors: Ricardo Clark-tapia, Francisco Molina-freanerAbstract: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=75%) but moderate levels of heterozygosity were detected (H(o)=0.103 and H(e)=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=0.60), moderate differentiation among populations (theta=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.
Ashish Kumar Asthana - One of the best experts on this subject based on the ideXlab platform.
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Riccia boliviensis Jovet-Ast, New to Asia from India with Disjunct Distribution Beyond South America
National Academy Science Letters-india, 2020Co-Authors: Ashish Kumar Asthana, P. SrivastavaAbstract:Riccia boliviensis Jovet-Ast is recorded for the first time in Asia from the Eastern Ghats area of Andhra Pradesh (India). It is a Disjunct Distribution of this taxon recorded in Asia beyond South America as earlier it was reported from Argentina, Brazil, Venezuela and Bolivia (South America). The species can be readily distinguished in having spores exhibiting prominent triradiate mark and vermiculate sculpturing on its proximal face, while distal surface has sinuose ridges forming areolation at some places with tubercles at angles. Morpho-taxonomic account of Indian plants with Distributional map is provided in the present contribution.
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new report of trachyphyllum borgenii renauld cardot broth bryophyta from india with a note on its Disjunct Distribution in madagascar
National Academy Science Letters-india, 2019Co-Authors: Reesa Gupta, Ashish Kumar AsthanaAbstract:The present study highlights the Disjunct Distribution of the moss Trachyphyllum borgenii (Renauld & Cardot) Broth. Trachyphyllum borgenii, was earlier known as an endemic to Madagascar, has recently been identified at Pachmarhi Biosphere Reserve (PBR), central India. The discovery of T. borgenii is a new record for Indian subcontinent with extended range of Distribution from Madagascar and now it can be designated as a species with Disjunct Distribution instead of an endemic species.
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New report of Trachyphyllum borgenii (Renauld & Cardot) Broth. (Bryophyta) from India with a Note on Its Disjunct Distribution in Madagascar
National Academy Science Letters, 2018Co-Authors: Reesa Gupta, Ashish Kumar AsthanaAbstract:The present study highlights the Disjunct Distribution of the moss Trachyphyllum borgenii (Renauld & Cardot) Broth. Trachyphyllum borgenii, was earlier known as an endemic to Madagascar, has recently been identified at Pachmarhi Biosphere Reserve (PBR), central India. The discovery of T. borgenii is a new record for Indian subcontinent with extended range of Distribution from Madagascar and now it can be designated as a species with Disjunct Distribution instead of an endemic species.
Krystal A. Tolley - One of the best experts on this subject based on the ideXlab platform.
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Investigating the cause of the Disjunct Distribution of Amietophrynus pantherinus, the Endangered South African western leopard toad
Conservation Genetics, 2009Co-Authors: G. John Measey, Krystal A. TolleyAbstract:More amphibians are threatened through loss of habitat than any other single factor. Conservation measures to restore habitat are dependent on historical data indicating the original extent of a species. When historical data is absent, Disjunct Distributions create a special problem for conservationists who need to determine whether they have an anthropogenic cause. The Endangered western leopard toad (Amietophrynus pantherinus) has a Disjunct Distribution in the south-western tip of South Africa. We use mitochondrial sequences from 153 individuals to show that the Disjunct Distribution is unlikely to have an anthropogenic origin. Two distinct populations are separated by 100 km, with highest probability for the most recent common ancestor arising some 5 Kya. The causes of this Disjunct Distribution appear to be too recent to be attributable to changes in sea level; instead we suggest that there was a range retraction associated with a distinct drying period in the area during the Holocene, possibly indicating that this species will be susceptible to future climate change. Further, we find that the eastern population is less genetically diverse and appears to be undergoing a serious reduction in range, despite its occurrence in the least urbanized habitat. Conservation measures suggested include surveys for breeding sites in the eastern population, custodian agreements for existing breeding sites and foraging areas and the need for a Biodiversity Management Plan to be drawn up and implemented.
Quentin C. B. Cronk - One of the best experts on this subject based on the ideXlab platform.
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Phylogeny and Disjunct Distribution: evolution of Saintpaulia (Gesneriaceae).
Proceedings of The Royal Society B: Biological Sciences, 1997Co-Authors: Michael Moller, Quentin C. B. CronkAbstract:The molecular phylogeny of African violets (Saintpaulia H. Wendl.), based on ribosomal DNA internal transcribed spacer (ITS) sequences, follows the Disjunct biogeography of the genus. Sequence anal...