scholarly journals Genomic Screening Reveals That the Endangered Eucalyptus paludicola (Myrtaceae) Is a Hybrid

Diversity ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 468
Author(s):  
Kor-jent van Dijk ◽  
Michelle Waycott ◽  
Joe Quarmby ◽  
Doug Bickerton ◽  
Andrew H. Thornhill ◽  
...  
Keyword(s):  
High Throughput Sequencing ◽  
South Australia ◽  
Hybrid Origin ◽  
F1 Hybrids ◽  
Management Options ◽  
Hybrid Species ◽  
Conservation Implications ◽  
Hybrid Class ◽  
Low Incidence ◽  
Stable Hybrid

A hybrid origin for a conservation listed taxon will influence its status and management options. Here, we investigate the genetic origins of a nationally endangered listed taxon—Eucalyptus paludicola—a tree that is restricted to the Fleurieu Peninsula and Kangaroo Island of South Australia. Since its description in 1995, there have been suggestions that this taxon may potentially be a stable hybrid species. Using a high throughput sequencing approach, we developed a panel of polymorphic loci that were screened across E. paludicola and its putative parental species E. cosmophylla and E. ovata. Bayesian clustering of the genotype data identified separate groups comprising E. ovata and E. cosmophylla while E. paludicola individuals were admixed between these two, consistent with a hybrid origin. Hybrid class assignment tests indicate that the majority of E. paludicola individuals (~70%) are F1 hybrids with a low incidence of backcrossing. Most of the post-F1 hybrids were associated with revegetation sites suggesting they may be maladapted and rarely reach maturity under natural conditions. These data support the hypothesis that E. paludicola is a transient hybrid entity rather than a distinct hybrid species. We briefly discuss the conservation implications of our findings.

scholarly journals Natural hybridization between two butterfly bushes in Tibet: dominance of F1 hybrids promotes strong reproductive isolation   

2020 ◽  
Author(s):  
Rongli Liao ◽  
Weibang Sun ◽  
Yongpeng Ma
Keyword(s):  
Reproductive Isolation ◽  
Parental Species ◽  
Morphological Characters ◽  
Natural Hybridization ◽  
Hybrid Origin ◽  
F1 Hybrids ◽  
Evolutionary Significance ◽  
Sympatric Populations ◽  
Hybrid Species ◽  
Intergenic Spacers

Abstract Background: F1 hybrids acting as a bridgehead for producing later generation hybrids can have evolutionary significance through strengthening reproductive isolation or facilitating gene flow between parental species, depending on whether backcrossing can occur. It had been suggested that the Tibetan plant Buddleja wardii was a hybrid species between B. alternifolia and B. crispa based on their sympatric distributions and the morphological characters in last century. Till now however, we still have limited evidence to prove key issues to B. wardii, like if it is of hybrid origin indeed and whether it is currently a true hybrid species already.Results: In the present study, two sympatric populations of these three taxa were examined and compared using four nuclear genes and three chloroplast intergenic spacers, as well as with 10 morphological characters. Our results suggest that at both sites B. × wardii was likely to be a hybrids between B. alternifolia and B. crispa, and moreover, most of the hybrids present were confirmed to be F1s. This was further supported by morphology as no transgressive characters were detected. B. crispa was found to be the maternal parent in one population (BH), while in the second population (TJ), it was difficult to distinguish the hybridization direction due to shared haplotypes of cpDNA between B. alternifolia and B. crispa. Conclusions: These results provide evidence that the natural hybrids between B. alternifolia and B. crispa mainly comprise F1 hybrids, which have subsequently been given the name B. wardii. The F1 hybrids have also contributed to strong reproductive isolation between parental species.

scholarly journals Natural Hybridization between Two Butterfly Bushes in Tibet: Dominance of F1 Hybrids Promotes Strong Reproductive Isolation

2020 ◽  
Author(s):  
Rongli Liao ◽  
Weibang Sun ◽  
Yongpeng Ma
Keyword(s):  
Reproductive Isolation ◽  
Parental Species ◽  
Morphological Characters ◽  
Natural Hybridization ◽  
Hybrid Origin ◽  
F1 Hybrids ◽  
Evolutionary Significance ◽  
Sympatric Populations ◽  
Hybrid Species ◽  
Intergenic Spacers

Abstract Background: F1 hybrids acting as a bridgehead for producing later generation hybrids can have evolutionary significance through strengthening reproductive isolation or facilitating gene flow between parental species, depending on whether backcrossing can occur. It had been suggested that the Tibetan plant Buddleja wardii was a hybrid species between B. alternifolia and B. crispa based on their sympatric distributions and the morphological characters in last century. Till now however, we still have limited evidence to prove key issues to B. wardii, like if it is of hybrid origin indeed and whether it is currently a true hybrid species already.Results: In the present study, two sympatric populations of these three taxa were examined and compared using four nuclear genes and three chloroplast intergenic spacers, as well as with 10 morphological characters. Our results suggest that at both sites B. × wardii was likely to be a hybrids between B. alternifolia and B. crispa, and moreover, most of the hybrids present were confirmed to be F1s. This was further supported by morphology as no transgressive characters were detected. B. crispa was found to be the maternal parent in one population (BH), while in the second population (TJ), it was difficult to distinguish the hybridization direction due to shared haplotypes of cpDNA between B. alternifolia and B. crispa. Conclusions: These results provide evidence that the natural hybrids between B. alternifolia and B. crispa mainly comprise F1 hybrids, which have subsequently been given the name B. wardii. The F1 hybrids have also contributed to strong reproductive isolation between parental species.

Ash dieback in the UK: A review of the ecological and conservation implications and potential management options

2014 ◽  
Vol 175 ◽  
pp. 95-109 ◽  
Author(s):  
R.J. Mitchell ◽  
J.K. Beaton ◽  
P.E. Bellamy ◽  
A. Broome ◽  
J. Chetcuti ◽  
...  
Keyword(s):  
Management Options ◽  
Ash Dieback ◽  
Conservation Implications ◽  
The Uk

Variation in Eucalyptus cypellocarpa L. Johnson in Victoria, and a new taxon form the Grampian Ranges and Anglesea

Brunonia ◽  
1987 ◽  
Vol 10 (2) ◽  
pp. 159 ◽  
Author(s):  
RJ Watson ◽  
PY Ladiges ◽  
AR Griffin
Keyword(s):  
Seedling Growth ◽  
Population Variation ◽  
Hybrid Origin ◽  
F1 Hybrids ◽  
New Taxon ◽  
Seedling Morphology ◽  
Shoot Ratio ◽  
Root Shoot Ratio ◽  
Previous Hypothesis ◽  
Minor Population

Patterns of variation in adult and seedling morphology, seedling growth and root/shoot ratios were assessed for populations of E. cypellocarpa, E. goniocalyx and equivocal populations from the Grampian Ranges and Anglesea. F1 hybrids of the two species were also produced to assist evaluation of a previous hypothesis of phantom hybrid origin. The Grampians populations were similar to E. cypellocarpa in adult morphology, but had distinctly different seedlings that were not the same as the F1 hybrids. The Anglesea population, although intermediate between E. cypellocarpa and E. goniocalyx in some adult characters, had the same seedling form, including root/shoot ratio, and the same bark type as the Grampians populations. The study provided no evidence to support the hypothesis of a phantom hybrid origin for the Grampians and Anglesea forms. A more parsimonious interpretation is evolution by the splitting of an ancestral taxon. The Grampians and Anglesea populations are described as E. alaticaulis sp. nov., with minor population variation being interpreted as a result of geographic disjunction.

Cytoplasmic male sterility in Desmodium

1969 ◽  
Vol 20 (2) ◽  
pp. 227 ◽  
Author(s):  
KS McWhirter
Keyword(s):  
Cytoplasmic Male Sterility ◽  
Male Sterility ◽  
Interspecific Hybrid ◽  
Pollen Fertility ◽  
Pollen Sterility ◽  
Hybrid Origin ◽  
F1 Hybrids ◽  
Male Sterile ◽  
Genetic Stocks

A type of male sterility found in two Desmodium plants of probably interspecific hybrid origin was cytoplasmically inherited. The cytoplasmic male-sterile character was incorporated in the tropical legume Desmodium sandwicense by backcrossing. In this genetic background pollen sterility was complete. The male-sterile character was not graft-transmissible, and it produced no detectable pleiotropic effects on growth and development. Desmodium intortum gave restoration of pollen fertility in Fl hybrids with male-sterile lines of D. sandwicense. Restored F1 hybrids produced apparently normal pollen, but tests of functional ability of the pollen disclosed that pollen fertility was less than that of Fl hybrids with normal cytoplasm. Incomplete restoration of fertility was not due to heterozygosity of fertility-restoring genes with gametophytic expression, since fertility-restoring genes were shown to act sporophytically. The results established the occurrence in the legume Desmodium of a system of determination of the male-sterile, fertility-restored phenotypes that is similar to the cytoplasmic male sterility systems described in many other angiosperm plants. A scheme utilizing the genetic stocks produced in this study for commercial production of the interspecific hybrid D. sandwicense x D. intortum as a cultivar is presented.

The current and future projected distribution of Solanum hoplopetalum (Solanaceae): an indigenous weed of the south-western Australian grain belt

2012 ◽  
Vol 60 (2) ◽  
pp. 128 ◽  
Author(s):  
Pippa J. Michael ◽  
Paul B. Yeoh ◽  
John K. Scott
Keyword(s):  
Climate Change ◽  
Current Distribution ◽  
South Australia ◽  
Climate Change Scenarios ◽  
Management Options ◽  
South Wales ◽  
Major Factors ◽  
Lower South ◽  
Significant Match ◽  
Western Australian

The factors determining the distribution of the Western Australian endemic Solanum hoplopetalum Bitter & Summerh. (Solanaceae) were assessed because it was identified as a potential weed risk to Australian cropping regions, including under climate change scenarios. Incubation at constant temperatures determined daily plant growth rates and plants required 1380 degree-days above a threshold of 12.4°C to complete growth to flowering. From this and published information on the plant’s biology, we developed a mechanistic niche model using CLIMEX. The model projection for current climates produced a highly significant match to known distribution records. Spatially, the lower south-west and areas eastwards to South Australia, western New South Wales and southern parts of the Northern Territory were climatically suitable for growth of S. hoplopetalum. However, by 2070 the area under risk decreases, with the projected distribution under climate change contracting southwards. We hypothesise that climatic extremes and edaphic factors, possibly high soil pH, may be major factors determining the current distribution of S. hoplopetalum. Containment on the southern edge of the current distribution, interstate quarantine and local eradication in new areas of invasion are recommended as management options to combat the potential for this native weed to spread.

Speciation by hybridization in phasmids and other insects

1990 ◽  
Vol 68 (8) ◽  
pp. 1747-1760 ◽  
Author(s):  
Luciano Bullini ◽  
Giuseppe Nascetti
Keyword(s):  
Hybrid Origin ◽  
Clonal Variation ◽  
Female Reproduction ◽  
Bisexual Species ◽  
Hybrid Species ◽  
Carausius Morosus ◽  
Origin And Evolution ◽  
Parthenogenetic Development ◽  
Hybrid Genome ◽  
Disturbed Habitats

Speciation by hybridization in insects has been recently recognized on the basis of isozyme and chromosome studies showing that several species, either diploid or polyploid, have genomes that combine the genes and chromosome sets of two (or more) bisexual species. Until this evidence became available, thelytokous invertebrates were all considered uniparental derivatives of bisexual species. In this paper, we review examples including the stick insects Bacillus whitei, B. atticus, B. lynceorum, Leptynia hispanica D, Clonopsis gallica, Carausius morosus; the grasshopper Warramaba virgo; some Otiorrhynchus weevils; the planthopper Muellerianella 2-fairmairei–brevipennis; and black flies of the genera Gymnopais and Prosimulium. For several species (e.g., Warramaba virgo and Bacillus whitei), both parental taxa have been recognized, and their hybrid origin has been genetically assessed. In others (e.g., B. atticus), only one of the bisexual parental species has been detected; but their hybrid origin is supported by strong evidence, at both the isozyme and chromosome levels. For other supposed hybrid species (e.g., Clonopsis gallica, Carausius morosus), no bisexual ancestors have been detected, possibly because competition with their hybrid derivatives has made them rare or extinct. Insect hybrid species may differ in their mode of reproduction (apomictic or automictic thelytokous parthenogenesis, gynogenesis), degree of ploidy, and genetic structure (level of heterozygosity, clonal variation). The parallels between insect and vertebrate hybrid species, in which this phenomenon has been recognized and widely studied in the past 50 years, are drawn. The main problems involved in the origin and evolution of hybrid species are discussed, with particular regard to (i) changes in the maturation divisions allowing the transmission of the hybrid genome to the next generation, and (ii) their successful adaptation. The "spontaneous" and "hybrid" theories for the origin of unisexual forms are compared, with regard to hybrid species. An origin of hybrid species from occasional parthenogenetic development of hybrid eggs produced in areas of extensive interspecific hybridization (e.g., disturbed habitats) is suggested. Hybridization would not itself cause changes in the maturation divisions (which are controlled by genes of tychoparthenogenetic eggs) but only favour their selection through heterosis. The role of the so-called "heterotic" advantage (resulting from high levels of heterozygosity) and "demographic" advantage (resulting from all-female reproduction) in the evolutionary success of hybrid species is discussed. It is concluded that habitat disturbance by man is favouring both the onset of hybrid species and their successful spread.

Molecular genetic evidence for allotetraploid hybrid speciation in the genus Crocus L. (Iridaceae)

Phytotaxa ◽  
2016 ◽  
Vol 258 (2) ◽  
pp. 121 ◽  
Author(s):  
ÁGNES MOSOLYGÓ-L ◽  
GÁBOR SRAMKÓ ◽  
SÁNDOR BARABÁS ◽  
LEVENTE CZEGLÉDI ◽  
ANDRÁS JÁVOR ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Phylogenetic Trees ◽  
Parental Species ◽  
Molecular Genetic ◽  
Parallel Evolution ◽  
Carpathian Basin ◽  
Hybrid Origin ◽  
F1 Hybrids ◽  
Aflp Data ◽  
F1 Hybrid

Although dysploidy and polyploidisation events are known to be important drivers in the evolutionary history of the genus Crocus, only a few examples of natural hybrid origins have so far been documented. Here, we describe the phylogenetic affinities of five taxa in the Crocus vernus species complex from the Carpathian Basin in Central Europe. Genetic variability was evaluated using chloroplast DNA sequences of the accD-psaI intergenic spacer and amplified fragment length polymorphism (AFLP) in combination with karyological observations. Genetic diversity and differentiation of the seven investigated Crocus species were also evaluated using AFLP data. We created a phylogenetic hypothesis using both sequences and AFLP fingerprinting data under maximum parsimony (MP). AFLPs were also analysed by means of multivariate statistics using principal coordinate (PCoA) analysis and Bayesian clustering (BC) to test for hybridity. Both the AFLP and plastid phylogenetic trees separated the taxa into two groups: (1) a ‘Balkan’ clade, and; (2) an ‘Adriatic’ clade. The Balkan clade contained Crocus heuffelianus samples and one Crocus vittatus from Croatia as well as Crocus tommasinianus samples from Hungary; the Adriatic clade included Crocus vittatus and Crocus vernus samples from Hungary and Croatia as well as Crocus neapolitanus from Italy. A hard incongruence was found in the placement of the Slovakian Crocus scepusiensis which clustered inside the Balkan clade on our plastid tree, while it fell in the Adriatic clade on the AFLP tree. The same populations occupied intermediate position on the PCoA plot. The BC analysis assigned all Crocus scepusiensis specimens as F1 hybrids, while Crocus vernus and Crocus heuffelianus were assigned as parental species. Together with our cytological investigation that determined a 2n=18 chromosome number of Crocus scepusiensis, we conclude an allopolyploid hybrid origin for this Northern Carpathian taxon as the result of a cross between members of the 2n=10 Balkan clade (e.g., Crocus heuffelianus from Transylvania) and the 2n=8 Adriatic clade (Crocus vernus). A similar origin is postulated for the North Balkan Crocus vittatus (2n=18), which was clustered as an F1 hybrid in the BC analysis; thus, parallel evolution may have taken place in the northern and southern part of the Carpathian Basin beginning from the same parental species but leading to different allopolyploid derivatives.

scholarly journals Prenatal Diagnosis of Neuroblastoma

2014 ◽  
Vol 8 (3) ◽  
pp. 321-327
Author(s):  
Mona Zvanca ◽  
Cristian Andrei
Keyword(s):  
Prenatal Diagnosis ◽  
Case Reports ◽  
Case Series ◽  
Expectant Management ◽  
Individual Case ◽  
Management Options ◽  
Tertiary Center ◽  
Low Incidence ◽  
Tumor In Childhood

ABSTRACT Fetal malignancies are rare complications during pregnancies, but when they appear, they are very challenging for the perinatology team. Because of their low incidence, the information is limited, with data provided from individual case reports or small case series. Although neuroblastoma is the most frequent extracranial solid tumor in childhood, prenatal diagnosis by ultrasound is very rare and almost always discovered during routine third trimester ultrasound. Expectant management is usually indicated prenatally, with serial ultrasound examination. Delivery should be planned in a tertiary center together with pediatric oncologists and surgeons to allow appropriate postnatal management. We present two cases of neuroblastoma diagnosed at 36 and 33 weeks of gestation with multiple aspects of this tumor identified by ultrasound. Both cases needed surgery and had a favorable outcome. The key role of ultrasound in diagnosis and follow-up of neuroblastoma in pregnancy is discussed, together with the management options recommended in literature. How to cite this article Andrei C, Vladareanu R, Zvanca M, Vladareanu S. Prenatal Diagnosis of Neuroblastoma. Donald School J Ultrasound Obstet Gynecol 2014;8(3):321-327.

Hybrid Origin and Genomic Mosaicism of Dubautia scabra (Hawaiian Silversword Alliance; Asteraceae, Madiinae)

2008 ◽  
Vol 33 (3) ◽  
pp. 589-597 ◽  
Author(s):  
Elizabeth A. Friar ◽  
Linda M. Prince ◽  
Jennifer M. Cruse-Sanders ◽  
Mitchell E. McGlaughlin ◽  
Charles A. Butterworth ◽  
...  
Keyword(s):  
Single Copy ◽  
Nuclear Genes ◽  
Hybrid Origin ◽  
Internal Transcribed Spacer Region ◽  
Hybrid Species ◽  
Cytogenetic Data ◽  
Molecular Phylogenetic ◽  
Distinct Lineage ◽  
Phylogenetic Hypotheses ◽  
Genomic Regions

Incongruence among different estimates of species relationships in plants, from different molecules, cytogenetic data, biogeographic data, morphological/anatomical data or other sources, has been used frequently as an indication of introgression, hybrid species origin, or chloroplast (cp) capture. In plants, these incongruences are most often seen between data derived from the nuclear vs. the cp genomes and the nuclear markers used for comparison usually have been from the nuclear ribosomal (nr) internal transcribed spacer region (ITS). The amount of genomic material shared between introgressing species can be highly variable. In some of these cases, other nuclear genomic regions have moved between species without leaving a signature on the nrITS. An example of well-supported phylogenetic incongruence is the placement of Dubautia scabra (DC.) D. D. Keck in the Hawaiian silversword alliance (HSA); evolutionary hypotheses for D. scabra based on molecular as opposed to cytogenetic data are strongly discordant. In this paper, we test these two conflicting phylogenetic hypotheses regarding the evolutionary relationships of Dubautia scabra using evidence from six low-copy nuclear genes, as well as multiple chloroplast noncoding regions and nrITS. The nrITS region is also examined for the presence of multiple copy types. Incongruence between inferred relationships based on nuclear chromosomal arrangements and molecular phylogenetic data from chloroplast DNA and nrITS is resolved in favor of a hypothesis of ancient hybridization rather than cytogenetic homoplasy involving dysploidy. Most single-copy nuclear genes track histories of D. scabra compatible with cytogenetic data whereas chloroplast and nrITS data track a common, different history that appears to reflect hybridization with a chromosomally distinct lineage that also occurs on Maui Nui and Hawai'i (the Big Island).

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