Crosses, Genetic

Publication Title: 
Aging Cell

Molecular advances of the past decade have led to the discovery of a myriad of 'aging genes' (methuselah, Indy, InR, Chico, superoxide dismutase) that extend Drosophila lifespan by up to 85%. Despite this life extension, these mutants are no longer lived than at least some recently wild-caught strains. Typically, long-lived mutants are identified in relatively short-lived genetic backgrounds, and their effects are rarely tested in genetic backgrounds other than the one in which they were isolated or derived.

Author(s): 
Spencer, Christine C.
Howell, Christine E.
Wright, Amber R.
Promislow, Daniel E. L.
Publication Title: 
Human Molecular Genetics

In amyotrophic lateral sclerosis (ALS), the progressive loss of motor neurons is accompanied by extensive muscle denervation, resulting in paralysis and ultimately death. Upregulation of amyloid beta (A4) precursor protein (APP) in muscle fibres coincides with symptom onset in both sporadic ALS patients and the SOD1(G93A) mouse model of familial ALS.

Author(s): 
Bryson, J. Barney
Hobbs, Carl
Parsons, Michael J.
Bosch, Karen D.
Pandraud, Amelie
Walsh, Frank S.
Doherty, Patrick
Greensmith, Linda
Publication Title: 
Ageing Research Reviews

The mouse has become the favorite mammalian model. Among the many reasons for this privileged position of mice is their genetic proximity to humans, the possibilities of genetically manipulating their genomes and the availability of many tools, mutants and inbred strains. Also in the field of aging, mice have become very robust and reliable research tools.

Author(s): 
Vanhooren, Valerie
Libert, Claude
Publication Title: 
PloS One

Pollinator behaviour directly affects patterns of pollen movement and outcrossing rates in plants. In orchids pollinated by sexual deception of insects, patterns of pollen movement are primarily determined by the mate-searching behaviour of the deceived males. Here, using a capture-mark-recapture study (CMR) and dietary analysis, we compare mate-searching behaviour in relation to local abundance of two pollinator species and explore the implications for pollen movement in sexually deceptive Drakaea (Orchidaceae). Drakaea are pollinated solely by the sexual deception of male thynnine wasps.

Author(s): 
Menz, Myles H. M.
Phillips, Ryan D.
Dixon, Kingsley W.
Peakall, Rod
Didham, Raphael K.
Publication Title: 
Growth hormone & IGF research: official journal of the Growth Hormone Research Society and the International IGF Research Society

OBJECTIVE: Since a reduction of the insulin/IGF-1 signaling cascade extends life span in many species and IGF-1 signaling might partly mediate the effects of caloric restriction (CR), an experimental intervention for increasing longevity, the purpose of the present study was to use quantitative trait loci (QTL) analysis, an unbiased genetic approach, to identify particular regions of the genome influencing plasma IGF-1 levels in an F2 intercross between F344 and LOU/C rats; the latter being an inbred strain of Wistar origin, considered as a model of healthy aging since it resists to age (an

Author(s): 
Marissal-Arvy, Nathalie
Duron, Emmanuelle
Parmentier, Frédéric
Zizzari, Philippe
MormËde, Pierre
Epelbaum, Jacques
Publication Title: 
Cell

The amplification of ribosomal DNA during development of the somatic macronucleus in Tetrahymena thermophila was analyzed by genetic and molecular biological techniques. We have identified an alternate form of the rDNA, structurally distinguishable from the wild-type by an extra cutting site for Bam HI in its nontranscribed spacer. The altered rDNA was inherited in crosses in a simple Mendelian fashion, consistent with the presence of only one rRNA gene copy per haploid genome in the micronucleus.

Author(s): 
Pan, W. C.
Orias, E.
Flacks, M.
Blackburn, E. H.
Publication Title: 
Genetics

Telomeres are an unusual component of the genome because they do not encode genes, but their structure and cellular maintenance machinery (which we define as "telotype") are essential for chromosome stability. Cells can switch between different phenotypic states. One such example is when they switch from maintenance mediated by telomerase (TERT telotype) to one of the two alternative mechanisms of telomere preservation (ALT I and ALT II telotype). The nature of this switch is largely unknown.

Author(s): 
Makovets, Svetlana
Williams, Tanya L.
Blackburn, Elizabeth H.
Publication Title: 
Genetics

The micronuclear genome of Tetrahymena thermophila contains Tel-1 elements that structurally resemble transposons. Here we present molecular evidence that Tel-1 transposon-like elements are mobile. The arrangements of Tel-1 elements in the micronuclear genomes of several T. thermophila strains and cell lines were assayed by Southern blotting. The molecular evidence for Tel-1 transposition is most striking in strains that have undergone unusual laboratory-induced meioses.

Author(s): 
Wyman, C.
Blackburn, E. H.
Publication Title: 
Genetics

The micronuclear genome of Tetrahymena thermophila contains Tel-1 elements that structurally resemble transposons. Here we present molecular evidence that Tel-1 transposon-like elements are mobile. The arrangements of Tel-1 elements in the micronuclear genomes of several T. thermophila strains and cell lines were assayed by Southern blotting. The molecular evidence for Tel-1 transposition is most striking in strains that have undergone unusual laboratory-induced meioses.

Author(s): 
Wyman, C.
Blackburn, E. H.
Publication Title: 
Genetics

The abundant rDNA minichromosome of Tetrahymena thermophila is generated by a series of developmentally controlled processing steps, termed rDNA maturation, during the formation of the new macronucleus in conjugating cells. rDNA maturation involves excision of a region encoding the single copy rRNA gene (rDNA) from its germline location, rearrangement of the rDNA into a palindromic minichromosome, de novo telomere addition, and amplification to approximately 10(4) copies. The rDNA is maintained at this high level in vegetatively growing cells.

Author(s): 
Kapler, G. M.
Orias, E.
Blackburn, E. H.

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