Daytime light spectrum affects photoperiodic induction of vernal response in obligate spring migrants

Sur, Sayantan; Sharma, Aakansha; Malik, Indu; Bhardwaj, Sanjay Kumar; Kumar, Vinod

doi:10.1016/j.cbpa.2021.111017

Cited by 10 publications

(4 citation statements)

References 84 publications

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“…While chronotypes often refer to variation in the timing of daily events between individuals, recent behavioural studies on birds have elucidated the link between the timing of daily events and the timing of seasonal migration at the phenotypic level [ 66 ]. Further research on birds and fish has demonstrated a link between circadian and circannual rhythms, where hormonal pathways triggered by a photoperiod signal, for example via melatonin and thyroid hormones, result in a seasonal phenotype [ 67 , 68 ] ( figure 1 ). At the genotypic level, previous work on clock provided a tenuous link between genetic variation in genes central to daily rhythms and the timing of seasonal events, but this work was performed across rather than within populations [ 7 ].…”

Section: Discussionmentioning

confidence: 99%

Clock-linked genes underlie seasonal migratory timing in a diurnal raptor

et al. 2022

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Seasonal migration is a dynamic natural phenomenon that allows organisms to exploit favourable habitats across the annual cycle. While the morphological, physiological and behavioural changes associated with migratory behaviour are well characterized, the genetic basis of migration and its link to endogenous biological time-keeping pathways are poorly understood. Historically, genome-wide research has focused on genes of large effect, whereas many genes of small effect may work together to regulate complex traits like migratory behaviour. Here, we explicitly relax stringent outlier detection thresholds and, as a result, discover how multiple biological time-keeping genes are important to migratory timing in an iconic raptor species, the American kestrel ( Falco sparverius ). To validate the role of candidate loci in migratory timing, we genotyped kestrels captured across autumn migration and found significant associations between migratory timing and genetic variation in metabolic and light-input pathway genes that modulate biological clocks ( top1, phlpp1, cpne4 and peak1) . Further, we demonstrate that migrating individuals originated from a single panmictic source population, suggesting the existence of distinct early and late migratory genotypes (i.e. chronotypes). Overall, our results provide empirical support for the existence of a within-population-level polymorphism in genes underlying migratory timing in a diurnally migrating raptor.

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Section: Discussionmentioning

confidence: 99%

Clock-linked genes underlie seasonal migratory timing in a diurnal raptor

et al. 2022

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“…We wanted to assess the differential effects of LHS on sleep-immune health; therefore, we measured the expression of genes involved in the cytokine (il1b, il6 and nfkb) and RNS (nos2) pathway, genes coding for melatonin (mel1a and mel1b) and glucocorticoid receptors (GRs) (nr3c1), and genes directly involved in sleep (ghrh and bdnf ) and arousal (camk2) promoting pathway. We used the partial gene sequences from previous studies [26,35], whereas degenerate primers were used to clone sequence of genes not available to us (see electronic supplementary material and methods for details). For qPCR, specific primers were designed using the online software Primer Quest program (https://eu.idtdna.com/Primer-Quest).…”

Section: (D) Measurement Of Mrna Expression Of Candidate Genesmentioning

confidence: 99%

Photoperiod-driven concurrent changes in hypothalamic and brainstem transcription of sleep and immune genes in migratory redheaded bunting

et al. 2023

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The molecular regulation of sleep in avian migrants is still obscure. We thus investigated this in migratory redheaded buntings, where four life-history states (LHS; i.e. non-migratory, pre-migratory, migratory and refractory states) were induced. There was increased night-time activity (i.e. Zugunruhe ) during the migratory state with reduced daytime activity. The recordings of the sleep–wake cycle in buntings showed increased night-time active wakefulness coupled with drastically reduced front and back sleep during migratory phase. Interestingly, we found the buntings to feed and drink even after lights-off during migration. Gene expression studies revealed increased hypothalamic expression of glucocorticoid receptor ( nr3c1 ), and pro-inflammatory cytokines ( il1b and il6 ) in pre-migratory and migratory states, respectively, whereas in brainstem Ca 2+ /calmodulin-dependent protein kinase 2 ( camk2 ) was upregulated during the migratory state. This suggested a heightened pro-inflammatory state during migration which is a feature of chronic sleep loss, and a possible role of Ca 2+ signalling in promoting wakefulness. In both the hypothalamus and brainstem, the expression of melatonin receptors ( mel1a and mel1b ) was increased in the pre-migratory state, and growth hormone-releasing hormone ( ghrh , known to induce sleep) was reduced during the migratory state. The current results demonstrate key molecules involved in the regulation of sleep–wake cycle across LHS in migratory songbirds.

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“…The reduced Th mRNA levels in castrates, compared to intact buntings, further supports this [ 89 ]. Interestingly, the expression of Th is modulated by the light quality and temperature suggesting a functional interaction of the hypothalamic thermosensitive and photoreceptive cells with dopaminergic neurons [ 67 , 90 ]. Photostimulated redheaded buntings showed higher hypothalamic Th mRNA levels when they were exposed to a short light wavelength (460 nm), compared to when they were exposed to a longer light wavelength (620 nm) [ 90 ].…”

Section: Unraveling the Genetic Control Of Migratory Behaviormentioning

confidence: 99%

“…Interestingly, the expression of Th is modulated by the light quality and temperature suggesting a functional interaction of the hypothalamic thermosensitive and photoreceptive cells with dopaminergic neurons [ 67 , 90 ]. Photostimulated redheaded buntings showed higher hypothalamic Th mRNA levels when they were exposed to a short light wavelength (460 nm), compared to when they were exposed to a longer light wavelength (620 nm) [ 90 ]. Likewise, the exposure to a stimulatory photoperiod at 35 °C led to an increased Th mRNA expression, compared to levels at 22 °C, in both the midbrain and hypothalamus of migratory blackheaded buntings ( Figure 2 , [ 67 ]).…”

Section: Unraveling the Genetic Control Of Migratory Behaviormentioning

confidence: 99%

Genetic Control of Avian Migration: Insights from Studies in Latitudinal Passerine Migrants

Sharma

Sur

Tripathi

et al. 2023

Genes

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Twice-a-year, large-scale movement of billions of birds across latitudinal gradients is one of the most fascinating behavioral phenomena seen among animals. These seasonal voyages in autumn southwards and in spring northwards occur within a discrete time window and, as part of an overall annual itinerary, involve close interaction of the endogenous rhythm at several levels with prevailing photoperiod and temperature. The overall success of seasonal migrations thus depends on their close coupling with the other annual sub-cycles, namely those of the breeding, post-breeding recovery, molt and non-migratory periods. There are striking alterations in the daily behavior and physiology with the onset and end of the migratory period, as shown by the phase inversions in behavioral (a diurnal passerine bird becomes nocturnal and flies at night) and neural activities. Interestingly, there are also differences in the behavior, physiology and regulatory strategies between autumn and spring (vernal) migrations. Concurrent molecular changes occur in regulatory (brain) and metabolic (liver, flight muscle) tissues, as shown in the expression of genes particularly associated with 24 h timekeeping, fat accumulation and the overall metabolism. Here, we present insights into the genetic basis of migratory behavior based on studies using both candidate and global gene expression approaches in passerine migrants, with special reference to Palearctic-Indian migratory blackheaded and redheaded buntings.

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Daytime light spectrum affects photoperiodic induction of vernal response in obligate spring migrants

Cited by 10 publications

References 84 publications

Clock-linked genes underlie seasonal migratory timing in a diurnal raptor

Clock-linked genes underlie seasonal migratory timing in a diurnal raptor

Photoperiod-driven concurrent changes in hypothalamic and brainstem transcription of sleep and immune genes in migratory redheaded bunting

Genetic Control of Avian Migration: Insights from Studies in Latitudinal Passerine Migrants

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