Unisexual salamanders (genus Ambystoma) present a new reproductive mode for eukaryotes

Genome ◽  
2007 ◽  
Vol 50 (2) ◽  
pp. 119-136 ◽  
Author(s):  
James P. Bogart ◽  
Ke Bi ◽  
Jinzong Fu ◽  
Daniel W.A. Noble ◽  
John Niedzwiecki
Keyword(s):  
Intergenic Spacer ◽  
Reproductive Mode ◽  
Sister Group ◽  
Intergenic Spacer Region ◽  
Sexual Species ◽  
Reproductive Modes ◽  
Ambystoma Barbouri ◽  
Time Of Divergence ◽  
Relationship Of ◽  
Microsatellite Alleles

To persist, unisexual and asexual eukaryotes must have reproductive modes that circumvent normal bisexual reproduction. Parthenogenesis, gynogenesis, and hybridogenesis are the modes that have generally been ascribed to various unisexuals. Unisexual Ambystoma are abundant around the Great Lakes region of North America, and have variously been described as having all 3 reproductive modes. Diploid and polyploid unisexuals have nuclear genomes that combine the haploid genomes of 2 to 4 distinct sexual species, but the mtDNA is unlike any of those 4 species and is similar to another species, Ambystoma barbouri . To obtain better resolution of the reproductive mode used by unisexual Ambystoma and to explore the relationship of A. barbouri to the unisexuals, we sequenced the mitochondrial control and highly variable intergenic spacer region of 48 ambystomatids, which included 28 unisexuals, representatives of the 4 sexual species and A. barbouri. The unisexuals have similar sequences over most of their range, and form a close sister group to A. barbouri, with an estimated time of divergence of 2.4–3.9 million years ago. Individuals from the Lake Erie Islands (Kelleys, Pelee, North Bass) have a haplotype that demonstrates an isolation event. We examined highly variable microsatellite loci, and found that the genetic makeup of the unisexuals is highly variable and that unisexual individuals share microsatellite alleles with sexual individuals within populations. Although many progeny from the same female had the same genotype for 5 microsatellite DNA loci, there was no indication that any particular genome is consistently inherited in a clonal fashion in a population. The reproductive mode used by unisexual Ambystoma appears to be unique; we suggest kleptogenesis as a new unisexual reproductive mode that is used by these salamanders.

Phylogeny of the Proteaceae based on atpB and atpB-rbcL intergenic spacer region sequences

1998 ◽  
Vol 11 (4) ◽  
pp. 301 ◽  
Author(s):  
Sara B. Hoot ◽  
Andrew W. Douglas
Keyword(s):  
Chromosome Doubling ◽  
Intergenic Spacer ◽  
Sister Group ◽  
Morphological Characters ◽  
Molecular Data ◽  
Homogeneity Test ◽  
Nucleotide Substitutions ◽  
Data Set ◽  
Intergenic Spacer Region ◽  
Pollen Presentation

Parsimony analyses were conducted for 46 genera representing all subfamilies and tribes within Proteaceae using two chloroplast sequences: the gene atpB and the noncoding spacer region between atpB and rbcL. The spacer region was more variable than atpB and provided insertion and deletion data as well as nucleotide substitutions. The atpB and spacer region data sets were highly congruent (as indicated by the partition homogeneity test) and were analysed separately and combined. Both unweighted and weighted character states (3 : 1 correction for transition bias) for the atpB data resulted in very similar strict consensus trees. In addition, the large subfamilies Proteoideae and Grevilleoideae were analysed separately, using appropriate outgroups determined by the analyses with complete sampling. The results from the combination of data were better resolved and supported than the results from each separate data set, although the Grevilleoideae were highly unresolved in all analyses. Most subfamilies in the Proteaceae were essentially monophyletic, but most tribes and subtribes were not. Bellendena is weakly supported as the sister group to all remaining members of the Proteaceae. Monotypic Eidotheoideae is well supported as a member of Proteoideae. Carnarvonioideae and Sphalmioideae are strongly supported as closely allied to the Grevilleoideae, but their positions in relation to this subfamily are unresolved. Other unusual alliances supported by our molecular data are: Isopogon–Adenanthos–Leucadendron–Protea, Petrophile–Aulax, Cardwellia–Euplassa–Gevuina, and Opisthiolepis–Buckinghamia–Grevillea. The tree resulting from the combined data showed limited congruence with morphological characters (flower pairs, stylar pollen presentation, and ovule number). Congruence with chromosome number was minimal, but our tree does support previous hypotheses of multiple aneuploidy and chromosome doubling events. The African and South American genera included in our analysis are dispersed among various clades with taxa from Australia and Asia, suggesting a former Gondwanian distribution for Proteaceae.

Characterization of the Reproductive Mode in Guayule In Vitro

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 483a-483
Author(s):  
Roy N. Keys ◽  
Dennis T. Ray ◽  
David A. Dierig
Keyword(s):  
Field Experiments ◽  
Reproductive Mode ◽  
Dichlorophenoxyacetic Acid ◽  
Initial Field ◽  
Breeding Lines ◽  
Reproductive Modes ◽  
Desert Southwest ◽  
2,4 Dichlorophenoxyacetic Acid

Guayule (Parthenium argentatum Gray, Asteraceae) is a latex-producing perennial desert shrub that is potentially of economic importance as an industrial crop for the desert Southwest. It is known to possess complex reproductive modes. Diploids are predominantly sexual and self-incompatible, while polyploids show a range of apomictic potential and self-compatibility. This paper describes the development of a relatively rapid and simple technique for characterizing reproductive modes of breeding lines of P. argentatum. Initial field experiments were based on an auxin test used successfully to characterize reproductive mode in the Poaceae. The application of 2,4-dichlorophenoxyacetic acid inhibited embryo formation in P. argentatum, but this was not the case with other auxins tested. Results of field experiments were ambiguous because: 1) the floral structure of P. argentatum is such that auxins might not have penetrated to the ovules, and 2) there was potential self-fertilization by pollen released within isolation bags. Therefore, in vitro culture of flower heads was tested because it provided much better control of environmental conditions, growth regulator application, and pollen release. Auxin alone, or in combination with gibberellic acid or kinetin, inhibited parthenogenesis in vitro. Embryo production did not vary using two substantially different nutrient media. In vitro flower head culture using a (Nitsch and Nitsch) liquid nutrient medium without growth regulators, enabled characterization of the reproductive mode of seven breeding lines, ranging from predominantly sexual to predominantly apomictic. The results of this technique were substantiated using RAPD analyzes of progeny arrays from controlled crosses.

Characterization of Fusarium spp. isolates by PCR-RFLP analysis of the intergenic spacer region of the rRNA gene (rDNA)

2006 ◽  
Vol 106 (3) ◽  
pp. 297-306 ◽  
Author(s):  
A. Llorens ◽  
M.J. Hinojo ◽  
R. Mateo ◽  
M.T. González-Jaén ◽  
F.M. Valle-Algarra ◽  
...  
Keyword(s):  
Intergenic Spacer ◽  
Rflp Analysis ◽  
Rrna Gene ◽  
Fusarium Spp ◽  
Intergenic Spacer Region ◽  
Pcr Rflp

scholarly journals The Western Progression of Lyme Disease: Infectious and NonclonalBorrelia burgdorferi Sensu LatoPopulations in Grand Forks County, North Dakota

2014 ◽  
Vol 81 (1) ◽  
pp. 48-58 ◽  
Author(s):  
Brandee L. Stone ◽  
Nathan M. Russart ◽  
Robert A. Gaultney ◽  
Angela M. Floden ◽  
Jefferson A. Vaughan ◽  
...  
Keyword(s):  
Lyme Disease ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
North Dakota ◽  
Intergenic Spacer ◽  
Rrna Gene ◽  
Content Type ◽  
Intergenic Spacer Region ◽  
Grand Forks ◽  
The 16S Rrna Gene

ABSTRACTScant attention has been paid to Lyme disease,Borrelia burgdorferi,Ixodes scapularis, or reservoirs in eastern North Dakota despite the fact that it borders high-risk counties in Minnesota. Recent reports ofB. burgdorferiandI. scapularisin North Dakota, however, prompted a more detailed examination. Spirochetes cultured from the hearts of five rodents trapped in Grand Forks County, ND, were identified asB. burgdorferi sensu latothrough sequence analyses of the 16S rRNA gene, the 16S rRNA gene-ileTintergenic spacer region,flaB,ospA,ospC, andp66. OspC typing revealed the presence of groups A, B, E, F, L, and I. Two rodents were concurrently carrying multiple OspC types. Multilocus sequence typing suggested the eastern North Dakota strains are most closely related to those found in neighboring regions of the upper Midwest and Canada. BALB/c mice were infected withB. burgdorferiisolate M3 (OspC group B) by needle inoculation or tick bite. Tibiotarsal joints and ear pinnae were culture positive, andB. burgdorferiM3 was detected by quantitative PCR (qPCR) in the tibiotarsal joints, hearts, and ear pinnae of infected mice. Uninfected larvalI. scapularisticks were able to acquireB. burgdorferiM3 from infected mice; M3 was maintained inI. scapularisduring the molt from larva to nymph; and further, M3 was transmitted from infectedI. scapularisnymphs to naive mice, as evidenced by cultures and qPCR analyses. These results demonstrate that isolate M3 is capable of disseminated infection by both artificial and natural routes of infection. This study confirms the presence of unique (nonclonal) and infectiousB. burgdorferipopulations in eastern North Dakota.

Genomic fingerprinting ofFrankiamicrosymbionts fromCeanothuscopopulations using repetitive sequences and polymerase chain reactions

1999 ◽  
Vol 77 (9) ◽  
pp. 1220-1230 ◽  
Author(s):  
Soon-Chun Jeong ◽  
David D Myrold
Keyword(s):  
Dna Sequencing ◽  
Dna Analysis ◽  
Repetitive Sequences ◽  
Intergenic Spacer ◽  
Rrna Genes ◽  
23S Rrna ◽  
Genomic Fingerprinting ◽  
Chain Reactions ◽  
Intergenic Spacer Region ◽  
Polymerase Chain

Specificity between Ceanothus species and their microsymbionts, Frankia, were investigated with nodules collected from three geographically separated copopulations of Ceanothus species. Nodules were analyzed using DNA sequencing and repetitive sequence polymerase chain reaction (rep-PCR) techniques. DNA sequencing of the intergenic spacer region between 16S and 23S rRNA genes suggested that Ceanothus-microsymbiotic Frankia are closely related at the intraspecific level. Diversity of the microsymbionts was further analyzed by genomic fingerprinting using repetitive sequences and PCR. A newly designed direct repeat (DR) sequence and a BOX sequence were used as PCR primers after justification that these primers can generate Frankia-specific fingerprints from nodule DNA. Analysis of the nodules using BOX- and DR-PCR showed that Ceanothus-microsymbiotic Frankia exhibited less diversity within each copopulation than among copopulations. These data suggested that geographic separation plays a more important role for divergence of Ceanothus-microsymbiotic Frankia than host plant.Key words: Frankia, Ceanothus, rep-PCR, diversity.

scholarly journals Intraspecific Variation in Cannabis sativa L. Based on Intergenic Spacer Region of Chloroplast DNA.

2000 ◽  
Vol 23 (6) ◽  
pp. 727-730 ◽  
Author(s):  
Mareshige KOHJYOUMA ◽  
I-Jung LEE ◽  
Osamu IIDA ◽  
Kogo KURIHARA ◽  
Kazuya YAMADA ◽  
...  
Keyword(s):  
Chloroplast Dna ◽  
Intraspecific Variation ◽  
Cannabis Sativa ◽  
Intergenic Spacer ◽  
Intergenic Spacer Region

scholarly journals Outbreak of Pitch Canker Caused by Fusarium circinatum on Pinus spp. in Northern Spain

Plant Disease ◽  
2005 ◽  
Vol 89 (9) ◽  
pp. 1015-1015 ◽  
Author(s):  
E. Landeras ◽  
P. García ◽  
Y. Fernández ◽  
M. Braña ◽  
O. Fernández-Alonso ◽  
...  
Keyword(s):  
Intergenic Spacer ◽  
Morphological Identification ◽  
Pitch Canker ◽  
Fusarium Circinatum ◽  
Northern Spain ◽  
Centraalbureau Voor ◽  
Canker Disease ◽  
Intergenic Spacer Region ◽  
Appl Environ ◽  
Pinus Spp

During the winter of 2003-2004, dieback symptoms were observed on Pinus radiata and P. pinaster in pine nurseries in Asturias (northern Spain). Small groups of affected seedlings appeared randomly distributed throughout the nurseries. The seedlings died rapidly, showing basal needle dieback, stem lesions, resin exudations, and wilting. Isolations from infected material onto potato dextrose agar (PDA) supplemented with 0.5 mg/ml of streptomycin sulfate and Komada's medium consistently yielded Fusarium sp. cultures. The isolates were transferred to PDA and Spezieller Nährstoffarmer agar and incubated at 25°C for 10 days with a 12-h photoperiod. The cultures were identified as Fusarium circinatum Nirenberg & O'Donnell (= Fusarium subglutinans Wollenweb. & Reinking), causal agent of pitch canker disease, on basis of the presence of polyphialides and characteristic sterile, coiled, hyphae (2). To further confirm their identity, a polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) based on histone H3 gene sequences (4) and a test based on the F. circinatum-specific primers, CIRC1A-CIRC4A, which amplifies a 360-bp DNA fragment of the intergenic spacer region of the nuclear ribosomal operon (3), were used. Results obtained with both techniques confirmed the morphological identification of the cultures. A representative culture has been placed in the Centraalbureau voor Schimmelcultures (CBS 117843). The pathogen was isolated only from seedlings of P. radiata and P. pinaster. Other species such as P. nigra, P. sylvestris, and Pseudotsuga menziesii, which were also grown in these nurseries, did not show symptoms. Pathogenicity was confirmed by inoculating 6- to 9-month-old P. radiata and P. pinaster seedlings. Small strips of bark (10 × 1 mm) were cut from the stems and similar sized pieces of PDA colonized by F. circinatum were placed in contact with the open wounds and covered with parafilm. Basal needle dieback was observed 10 days after inoculation that resulted in wilting of the seedlings. F. circinatum was reisolated from the affected stems fulfilling Koch's postulates. Later in the year, symptoms of pitch canker were also observed on 20-year-old P. radiata in one forest plantation in Cantabria (northern Spain). Infected branches and shoots of the trees exudated abundant resin, resulting in resinous cankers. The needles, distal to branch tip infections, wilt, fade to yellow then red, and fall from the tree. Affected trees showed noticeable crown dieback. The isolations from the cankers also yielded F. circinatum cultures that were identified as described above. Although a nonrefereed report appeared in 1998 (1), to our knowledge, this is the first report of F. circinatum on P. radiata and P. pinaster in Spain and in Europe. References: (1) L. D. Dwinell et al. Int. Congr. Plant Pathol. 7th. 3:9, 1998. (2) H. I. Nirenberg and K. O'Donnell. Mycologia 90:434, 1998. (3) W. Schweigkofler et al. Appl. Environ. Microbiol. 70:3512, 2004. (4) E. T. Steenkamp et al. Appl. Environ. Microbiol. 65:3401, 1999.

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