A cline in the Drosophila melanogaster period gene in Australia: neither down nor under

Abstract

Weeks et al. (2006) have reported their inability to find a cline in the frequencies of the major Thr‐Gly encoding length variant alleles of the period gene in Drosophila melanogaster in Eastern Australia. This is in contrast to a study by Sawyer et al. (2006), who found a cline on this continent from samples collected in 1993. Weeks et al. then cast doubt on the validity of a robust cline found for these variants in Europe by Costa et al. (1992), criticizing their molecular techniques and sampling methods. We show how these claims are unjustified, and reveal a number of potential problems in their own methodology. Finally by reanalysing the subset of their data which they state is more reliable, we suggest that their results from Australia may be reasonably consistent with our own.

Clock Gene Variation Is Associated with Breeding Phenology and Maybe under Directional Selection in the Migratory Barn Swallow

“…The ‘circadian clock’ senses temporal variation in light/dark cycles and produces a cascade of physiological processes that can ultimately cause adaptive behavioural shifts, such as flowering in plants, and preparing to and undertaking migration or breeding in birds [5], [10], [14], [15]. A large body of studies has led to the identification of several genes that are in control of the circadian clock and to the dissection of the molecular bases of circadian oscillations [15].…”

“…The ‘circadian clock’ senses temporal variation in light/dark cycles and produces a cascade of physiological processes that can ultimately cause adaptive behavioural shifts, such as flowering in plants, and preparing to and undertaking migration or breeding in birds [5], [10], [14], [15]. A large body of studies has led to the identification of several genes that are in control of the circadian clock and to the dissection of the molecular bases of circadian oscillations [15]. Clock gene networks have been characterized in organisms from fungi and plants to birds and mammals, and their functioning in producing biochemical circadian fluctuations shares similarities among phylogenetically distant taxa [16], [17].…”

Repeat variation in the human PER2 gene as a new genetic marker associated with cocaine addiction and brain dopamine D2 receptor availability

“…It therefore seems likely that positive selection affected clock genes in modern humans, and, as such, these genes would have sequence characteristics and genomic features absent in ancestral lineage. Intra-species clock variations have distinct geographic pattern of distribution, 30 suggesting that population-specific polymorphisms can enable highly adjustable regulation pattern required for population-specific adaptations.…”

Filogenia do Complexo Drosophila Buzzatii (Grupo Repleta): Inferências de Análises Multilocus Mitocondriais e Nucleares.

“…athabasca (Kliman & Hey, 1993;Ford et al 1994;Kyriacou et al 2007) e dos grupos D. virilis e D. willistoni (Hilton & Hey, 1996;Gleason & Powell, 1997). Além disso, homólogos ao gene period têm sido descritos em outros grupos, incluindo outros insetos (Barr et al 2005;Mazzotta et al 2005;Mazzoni et al 2006;Regier et al 2008), plantas (McClung, 2006) e vertebrados (Cahill, 2002;Reppert & Weaver, 2002).…”

“…Essa particularidade permite a utilização do gene period como marcador molecular tanto no nível intraespecífico quanto no interespecífico. De fato, esse gene tem sido utilizado em vários estudos comparativos em Drosophila, incluindo comparações entre espécies e populações dentro dos complexos D. melanogaster e D.athabasca (Kliman & Hey, 1993;Ford et al 1994;Kyriacou et al 2007) e dos grupos D. virilis e D. willistoni (Hilton & Hey, 1996;Gleason & Powell, 1997). Além disso, homólogos ao gene period têm sido descritos em outros grupos, incluindo outros insetos (Barr et al 2005;Mazzotta et al 2005;Mazzoni et al 2006;Regier et al 2008), plantas Em Drosophila, as regiões mais estudadas do gene period são as regiões C2 e N2, localizadas no éxon cinco (Figura 7).…”