New status, species, distribution records and phylogeny for Australian mandibulate Chironomidae (Diptera)

Abstract All life-history stages of the Australian Podonominae (Chironomidae) genus Archaeochlus Brundin are revised, providing evidence for recognition of a separate clade, named here as Austrochlus Cranston. Based on molecular and morphological evidence, the clade contains two additional species: Austrochlus parabrundini Cranston, Edward and Cook sp. n. is described from Western Australia where its granite outcrop seepage habitat and geographical range is almost identical to that of the type species Austrochlus brundini Cranston, Edward and Colless (n. comb); Austrochlus centralaustralis Cranston, Edward and Cook sp. n. is described from ephemeral seepage/flows in the MacDonnell and James Ranges of central Australia. Molecular studies reported here confirm species distinctions, relationships to African taxa, and basal relationships within the Chironomidae. Modelled distributions provide evidence for range restriction by seasonal rainfall patterns.     

Elucidation of the minimal sequence required to imprint H19 transgenes

The imprinted mouse H19 gene exhibits maternal allele-specific expression and paternal allele-specific hypermethylation. We previously demonstrated that a 14-kb H19 minitransgene possessing 5' differentially methylated sequence recapitulates the endogenous H19 imprinting pattern when present as high-copy arrays. To investigate the minimal sequences that are sufficient for H19 transgene imprinting, we have tested new transgenes in mice. While transgenes harboring limited or no 3' H19 sequence indicate that multiple elements within the 8-kb 3' fragment are required for appropriate imprinting, transgenes incorporating 1.7 kb of additional 5' sequence mimic the endogenous H19 pattern, including proper imprinting of low-copy arrays. One of these imprinted lines had a single 15.7-kb transgene integrant. This is the smallest H19 transgene identified thus far to display imprinting properties characteristic of the endogenous gene, suggesting that all cis-acting elements required for H19 imprinting in endodermal tissues reside within the 15.7-kb transgenic sequence.     

COULD A CLADOGRAM THIS SHORT HAVE ARISEN BY CHANCE ALONE?: ON PERMUTATION TESTS FOR CLADISTIC STRUCTURE

Abstract Absolute criteria for evaluating cladistic analyses are useful, not only because cladistic algorithms impose structure, but also because applications of cladistic results demand some assessment of the degree of corroboration of the cladogram. Here, a means of quantitative evaluation is presented based on tree length. The length of the most-parsimonious tree reflects the degree to which the observed characters co-vary such that a single tree topology can explain shared character states among the taxa. This “cladistic covariation” can be quantified by comparing the length of the most parsimonious tree for the observed data set to that found for data sets with random covariation of characters. A random data set is defined as one in which the original number of characters and their character states are maintained, but for each character, the states are randomly reassigned to the taxa. The cladistic permutation tail probability, PTP, is defined as the estimate of the proportion of times that a tree can be found as short or shorter than the original tree. Significant cladistic covariation exists if the PTP is less than a prescribed value, for example, 0.05. In case studies based on molecular and morphological data sets, application of the PTP shows that:

• 1 In the comparison of four different molecular data sets for orders of mammals, the sequence data set for alpha hemoglobin does not have significant cladistic covariation, while that for alpha crystallin is highly significant. However, when each data set was reduced to the 11 common taxa in order to standardize comparison, reduced levels of cladistic covariation, with no clear superiority of the alpha crystallin data, were found. Morphological data for these 11 taxa had a highly significant PTP, producing a tree roughly congruent with those for the three molecular sets with marginal or significant PTP values. Merging of all data sets, with the exclusion of the poorly structured alpha hemoglobin data, produced a data set with a significant PTP, and provides an estimate of the phylogenetic relationships among these 11 orders of mammals.
• 2 In an analysis of lactalbumin and lysozyme DNA sequence data for four taxa, purine-pyrimidine coding yields a data set with significant cladistic covariation, while other codings fail. The data for codon position 3 taken alone exhibit the strongest cladistic covariation.
• 3 A data set based on flavonoids in taxa of Polygonum initially yields a significant PTP; however, deletion of identically scored taxa leaves no significant cladistic covariation.
• 4 For mitochondrial DNA data on population genome types for four species of the crested newt, there is significant cladistic covariation for the set of all genome types, and among the five mtDNA genome types within one of the species. However, a conditional PTP test that assumes species monophyly shows that no significant cladistic covariation exists among the fur species for these data.
• 5 In an application of the test to a group of freshwater insects, as preliminary to biological monitoring, individual subsets of the taxonomic data representing larval, pupal, and adult stages had non-significant PTPs, while the complete data set showed significant cladistic structure.

     

Factors influencing Agrobacterium tumefaciens-mediated transformation and regeneration of the safflower cultivar ‘centennial’

The effects of co-cultivation conditions on transformation efficiency and direct shoot regeneration from seedling explants of safflower cv. Centennial were examined. Agrobacterium tumefaciens strain EHA105/p35SGUSInt was more infective than LBA4404/pBI121 as determined by numbers of sectors expressing -glucuronidase activity. Compared to nontransformed controls, efficiency of direct shoot regeneration was markedly decreased by co-cultivation with EHA105 and the decrease exacerbated by addition of acetosyringone, indicating that a hypersensitive response to bacterial infection may reduce organogenetic potential. Likewise exposure of co-cultivated explants to kanamycin or geneticin in selective media reduced regeneration efficiency. Addition of 500 mg l^-1 carbenicillin slightly increased numbers of regenerating shoots. Tranfformed shoots were obtained only when kanamycin selection was initiated 1 or 2 days after co-cultivation. Presence of transgenes in geneticin-resistant shoots was confirmed using polymerase chain reaction and Southern hybridization assays.Abbreviations AS acetosyringone - GUS -glucuronidase - MS Murashige and Skoog (1962) - NAA naphthaleneacetic acid - NPTII neomycin phosphotransferase II - PCR polymerase chain reaction - TDZ thidiazuron     

A new genus and species of Chironominae (Diptera: Chironomidae) with wood-mining larvae

Abstract  Xylochironomus kakadu , a new genus and species of wood-mining chironomid, is described from northern Australia. Formerly known by a code 'unknown genus K1', the larvae mine soft immersed timber in tropical Australia. The basal striae on the larval mandible are observed otherwise only in Chironomus Meigen and likely close relatives currently placed in Einfeldia Kieffer. The adult male could key as a tanytarsine, and all stages superficially resemble Polypedilum Kieffer, except for the bare squama and the non-tapered male tergite VIII, and the dorsal larval head sclerites. However, analyses of a morphological data matrix derived from all life history stages support no such relationships. Instead, a relationship to Paralauterborniella Lenz and Apedilum Townes, and at one remove, to Fissimentum Cranston & Nolte and Imparipecten Kieffer is postulated. Larval wood-mining among the early branching Chironomini is evidently frequent, but taxa appear not to form a monophyletic clade.