Month: September 2022

FRAGMENT FROM NATURE concludes this weekend on a biological consideration of a sense of place, in particular for peripatetic creatures, whose destiny is to constantly migrate across the globe. These animals have acute geographical sense, and often migrate to very specific destinations, covering many thousands of miles to end up at the exact same nest, for instance, like the swallows in my home. Navigation and timing, cues, and fasting metabolism during transit, all are complex issues. View in LinkedIn

GENE CLUSTER SPECULATION. "We would expect that phenotypic variation of correlated migratory traits is linked to genetic variation at a single closely linked gene cluster or a few ‘regulatory genes’ with multiple pleiotropic effects." https://lnkd.in/dapscwg View in LinkedIn

PHENOTYPIC VARIATION. "Across a range of organisms, related species or even populations of the same species exhibit strikingly different scales and patterns of movement. A significant proportion of the phenotypic variance in migratory traits is genetic, but the genes involved in shaping these phenotypes are still unknown." https://lnkd.in/eCZBnME View in LinkedIn

PHOTOPERIODIC TRIGGERS. "In long-lived animals, seasonal recurrence of biologic activities (phenology) like migration, hibernation, reproduction, and molt is achieved by adjusting the period of endogenous clocks to the annual change in the photoperiod. Responding to the environmental photoperiod cycle demands behavioral and physiologic plasticity, as shown by the development of seasonal phenotypes in many vertebrates." https://lnkd.in/eqEQSzy View in LinkedIn

SEASONAL PHENOTYPES. "This is particularly evident in latitudinal migratory species, which respond to photoperiod change with a precise succession of change in the behavior for accurate seasonal timing of their migration and reproduction." http://www.fasebj.org/content/29/10/4248.full View in LinkedIn

TRIGGERS FOR PHYSIOLOGY. "Such a change in the circadian activity patterns involves substantial physiological and hormonal shifts." http://rspb.royalsocietypublishing.org/content/early/2011/02/11/rspb.2010.2567 View in LinkedIn

CIRCADIAN CHANGES. "From a behavioural ecology perspective, the ability to shift circadian activity during migration represents a key element of avian migratory behaviour. Indeed, many species of diurnally active birds switch to additional nocturnal activity during the migratory season.” http://rspb.royalsocietypublishing.org/content/early/2011/02/11/rspb.2010.2567 View in LinkedIn

LIGHT IMPACT. "When continuously exposed to long days, short day photosensitive migratory birds show successive seasonal life-history states, characterized by premigratory (initiation of lipogenesis and gametogenesis), migratory (fat deposition and increased body mass, recrudesced gonads, and nocturnal migratory restlessness, known as Zugunruhe, and postmigratory [fat stores depleted and lean body mass, regressed gonads, return to day activity, and development of photorefractoriness; long day refractory)] phenotypes." http://www.fasebj.org/content/29/10/4248.full View in LinkedIn

CIRCADIAN CONTROL. "Circadian pacemaker in the suprachiasmatic nuclei shows phase plasticity with winter and summer photoperiod in seasonal mammals. In vertebrates, the circadian molecular oscillator is based on transcriptional-translational feedback loops, in which periods and cryptochromes are negative regulators of their own transcription driven by brain and muscle arnt-like protein 1 (Bmal1) and circadian locomotor output cycles kaput (Clock) transcriptional activators." http://www.fasebj.org/content/29/10/4248.full View in LinkedIn

"CLOCK POLYMORPHISM has been found to be associated with breeding in the blue tit (Cyanistes caeruleu) and migratory barn swallows (Hirundo rustica). Similarly, midday and midnight Ror-α and Rev-erb-α mRNA expressions have been found to vary with photoperiod-induced phenotypes in the night-migratory black-headed bunting (Emberiza melanocephala)." http://www.fasebj.org/content/29/10/4248.full View in LinkedIn