THE EFFECT OF DEVELOPMENTAL TEMPERATURE ON THE GENETIC ARCHITECTURE UNDERLYING SIZE AND THERMAL CLINES IN DROSOPHILA MELANOGASTER AND D. SIMULANS FROM THE EAST COAST OF AUSTRALIA

THE EFFECT OF DEVELOPMENTAL TEMPERATURE ON THE GENETIC ARCHITECTURE UNDERLYING SIZE AND THERMAL CLINES IN DROSOPHILA MELANOGASTER AND D. SIMULANS FROM THE EAST COAST OF AUSTRALIA: "

ABSTRACT

Body size and thermal tolerance clines in Drosophila melanogaster occur along the east coast of Australia. However the extent to which temperature affects the genetic architecture underlying the observed clinal divergence remains unknown. Clinal variation in these traits is associated with cosmopolitan chromosome inversions which cline in D. melanogaster. Whether this association influences the genetic architecture for these traits in D. melanogaster is unclear. D. simulans shows linear clines in body size, but non-linear clines in cold resistance. Clinally varying inversions are absent in D. simulans. Line-cross and clinal analyses were performed between tropical and temperate populations of D. melanogaster and D. simulans from the east coast of Australia to investigate whether clinal patterns and genetic effects contributing to clinal divergence in wing centroid size, thorax length, wing-to-thorax ratio, cold and heat resistance differed under different developmental temperatures (18°, 25° and 29°C). Developmental temperature influenced the genetic architecture in both species. Similarities between D. melanogaster and D. simulans suggest clinally varying inversion polymorphisms have little influence on the genetic architecture underlying clinal divergence in size in D. melanogaster. Differing genetic architectures across different temperatures highlight the need to consider different environments in future evolutionary and molecular studies of phenotypic divergence.

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MidExDB: A database of Drosophila CNS midline cell gene expression

MidExDB: A database of Drosophila CNS midline cell gene expression: "Background:
The Drosophila CNS midline cells are an excellent model system to study neuronal and glial development because of their diversity of cell types and the relative ease in identifying and studying the function of midline-expressed genes. In situ hybridization experiments generated a large dataset of midline gene expression patterns. To help synthesize these data and make them available to the scientific community, we developed a web-accessible database.DescriptionMidExDB (Drosophila CNS Midline Gene Expression Database) is comprised of images and data from our in situ hybridization experiments that examined midline gene expression. Multiple search tools are available to allow each type of data to be viewed and compared. Descriptions of each midline cell type and their development are included as background information.
Conclusion:
MidExDB integrates large-scale gene expression data with the ability to identify individual cell types providing the foundation for detailed genetic, molecular, and biochemical studies of CNS midline cell neuronal and glial development and function. This information has general relevance for the study of nervous system development in other organisms, and also provides insight into transcriptional regulation."

Adaptive Divergence in the Thyroid Hormone Signaling Pathway in the Stickleback Radiation

Adaptive Divergence in the Thyroid Hormone Signaling Pathway in the Stickleback Radiation: "Jun Kitano, Sean C. Lema, J. Adam Luckenbach, Seiichi Mori, Yui Kawagishi, Makoto Kusakabe, Penny Swanson, Catherine L. Peichel. During adaptive radiations, animals colonize diverse environments, which requires adaptation in multiple phenotypic traits [1]. Because hormones mediate the dynamic regulation of suites of phenoty...."

Effects of personality on territory defence in communication networks: a playback experiment with radio-tagged great tits

Effects of personality on territory defence in communication networks: a playback experiment with radio-tagged great tits: "

Individuals often differ consistently in behaviour across time and contexts, and such consistent behavioural differences are commonly described as personality. Personality can play a central role in social behaviour both in dyadic interactions and in social networks. We investigated whether explorative behaviour, as proxy of personality of territorial male great tits (Parus major), predicts their own and their neighbours' territorial responses towards simulated intruders. Several weeks prior to playback, subjects were taken from the wild to test their exploratory behaviour in a standard context in the laboratory. Exploratory behaviour provides a proxy of personality along a slow–fast explorer continuum. Upon release, males were radio-tracked and subsequently exposed to interactive playback simulating a more or a less aggressive territorial intruder (by either overlapping or alternating broadcast songs with the subjects' songs). At the same time, we radio-tracked a neighbour of the playback subject. Male vocal responses during playback and spatial movements after playback varied according to male explorative behaviour and playback treatment. Males with lower exploration scores approached the loudspeaker less, and sang more songs, shorter songs and songs with slower element rates than did males with higher exploration scores. Moreover, neighbour responses were related to the explorative behaviour of the subject receiving the playback but not to their own explorative behaviour. Our overall findings reveal for the first time how personality traits affect resource defence within a communication network providing new insights on the cause of variation in resource defence behaviour.

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I just like this one because the title made me laugh...

Dynamic evolution of precise regulatory encodings creates the clustered site signature of enhancers

Dynamic evolution of precise regulatory encodings creates the clustered site signature of enhancers: "

Dynamic evolution of precise regulatory encodings creates the clustered site signature of enhancers

Nature Communications 1, 99 (2010). doi:10.1038/ncomms1102

Authors: Justin Crocker, Nathan Potter & Albert Erives

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Systematic Protein Location Mapping Reveals Five Principal Chromatin Types in Drosophila Cells

Systematic Protein Location Mapping Reveals Five Principal Chromatin Types in Drosophila Cells: "Guillaume J. Filion, Joke G. van Bemmel, Ulrich Braunschweig, Wendy Talhout, Jop Kind, Lucas D. Ward, Wim Brugman, Inês J. de Castro, Ron M. Kerkhoven, Harmen J. Bussemaker, Bas van Steensel. Chromatin is important for the regulation of transcription and other functions, yet the diversity of chromatin composition and the distribution along chromosomes are still poorly characterized. By...."

Insights Into Species Divergence and the Evolution of Hermaphroditism From Fertile Interspecies Hybrids of Caenorhabditis Nematodes [Population and evolutionary genetics]

Insights Into Species Divergence and the Evolution of Hermaphroditism From Fertile Interspecies Hybrids of Caenorhabditis Nematodes [Population and evolutionary genetics]: "

The architecture of both phenotypic variation and reproductive isolation are important problems in evolutionary genetics. The nematode genus Caenorhabditis includes both gonochoristic (male/female) and androdioecious (male/hermaprodite) species. However, the natural genetic variants distinguishing reproductive mode remain unknown, and nothing is known about the genetic basis of postzygotic isolation in the genus. Here we describe the hybrid genetics of the first Caenorhabditis species pair capable of producing fertile hybrid progeny, the gonochoristic Caenorhabditis sp. 9 and the androdioecious C. briggsae. Though many interspecies F₁ arrest during embryogenesis, a viable subset develops into fertile females and sterile males. Reciprocal parental crosses reveal asymmetry in male-specific viability, female fertility, and backcross viability. Selfing and spermatogenesis are extremely rare in XX F₁, and almost all hybrid self-progeny are inviable. Consistent with this, F₁ females do not express male-specific molecular germline markers. We also investigated three approaches to producing hybrid hermaphrodites. A dominant mutagenesis screen for self-fertile F₁ hybrids was unsuccessful. Polyploid F₁ hybrids with increased C. briggsae genomic material did show elevated rates of selfing, but selfed progeny were mostly inviable. Finally, the use of backcrosses to render the hybrid genome partial homozygous for C. briggsae alleles did not increase the incidence of selfing or spermatogenesis relative to the F₁ generation. These hybrid animals were genotyped at 23 loci, and significant segregation distortion (biased against C. briggsae) was detected at 13 loci. This, combined with an absence of productive hybrid selfing, prevents formulation of simple hypotheses about the genetic architecture of hermaphroditism. In the near future, this hybrid system will likely be fruitful for understanding the genetics of reproductive isolation in Caenorhabditis.

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