Molecular basis of photoperiodic control of reproductive cycle in a subtropical songbird, the Indian weaver bird (Ploceus philippinus)

Srivastava, Amrita; Trivedi, Neerja; Malik, Shalie; Rani, Sangeeta; Kumar, Vinod

doi:10.1016/j.ygcen.2014.08.012

Cited by 9 publications

(8 citation statements)

References 30 publications

(44 reference statements)

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“…Our data support the hypothesis that GnRH stimulates gonadal recrudescence and reproductive development in male dark-eyed juncos, as we found that residents had significantly higher hypothalamic GnRH mRNA expression levels compared to migrants during the pre-breeding stage. These findings fit well with other avian studies that show an increase in GnRH mRNA expression levels during the transition from photosensitivity to photostimulation [40,41]. Additionally, increased expression of hypothalamic GnRH could be reflective of reduced sex steroid negative feedback, as we also found that residents had significantly lower rspb.royalsocietypublishing.org Proc.…”

Section: (A) Hypothalamic Gene Expressionsupporting

confidence: 91%

“…However, it is possible that we sampled our birds too late to detect a subspecies difference in hypothalamic GnIH mRNA expression, as residents may have dropped GnIH expression levels during the early prebreeding stage but by the time we sampled our birds, migrants had already lowered GnIH expression as well. Alternatively, decreases in hypothalamic GnIH may play a minor or insignificant role in gonadal recrudescence, as the rapid spike in hypothalamic GnIH mRNA expression during the end of breeding suggests that GnIH's major role is to promote gonadal regression as birds become photorefractory [40,41,43].…”

Section: (A) Hypothalamic Gene Expressionmentioning

confidence: 99%

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Seasonally sympatric but allochronic: differential expression of hypothalamic genes in a songbird during gonadal development

et al. 2018

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Allochrony, the mismatch of reproductive schedules, is one mechanism that can mediate sympatric speciation and diversification. In songbirds, the transition into breeding condition and gonadal growth is regulated by the hypothalamic–pituitary–gonadal (HPG) axis at multiple levels. We investigated whether the difference in reproductive timing between two seasonally sympatric subspecies of dark-eyed juncos ( Junco hyemalis ) was related to gene expression along the HPG axis. During the sympatric pre-breeding stage, we measured hypothalamic and testicular mRNA expression of candidate genes via qPCR in captive male juncos. For hypothalamic mRNA, we found our earlier breeding subspecies had increased expression of gonadotropin-releasing hormone ( GnRH ) and decreased expression of androgen receptor, oestrogen receptor alpha and mineralocorticoid receptor ( MR ). Subspecies did not differ in expression of hypothalamic gonadotropin-inhibitory hormone ( GnIH ) and glucocorticoid receptor ( GR ). While our earlier breeding subspecies had higher mRNA expression of testicular GR , subspecies did not differ in testicular luteinizing hormone receptor, follicle-stimulating hormone receptor or MR mRNA expression levels. Our findings indicate increased GnRH production and decreased hypothalamic sensitivity to sex steroid negative feedback as factors promoting differences in the timing of gonadal recrudescence between recently diverged populations. Differential gene expression along the HPG axis may facilitate species diversification under seasonal sympatry.

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Section: (A) Hypothalamic Gene Expressionsupporting

confidence: 91%

Section: (A) Hypothalamic Gene Expressionmentioning

confidence: 99%

Seasonally sympatric but allochronic: differential expression of hypothalamic genes in a songbird during gonadal development

et al. 2018

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“…In temperate and tropical bird species, [20][21][22][23][24][25] the seasonal reproductive response depends on photoperiodic control of thyrotropin beta subunit (Tshb) expression in the PT and consequent thyrotropin-receptor-mediated changes in MBH function exemplified by changes in the expression of the thyroid hormone deiodinase genes, Dio2 and Dio3. Similarly, in the Svalbard ptarmigan, Tshb expression in the PT was continuously suppressed under SP, and transfer to LL strongly induced Tshb expression, which peaked 13 h after lights on, i.e., circadian time 13 (CT 13) (Figure 1E; p < 0.0001 compared to SP control birds by Sidak's multiple comparisons test after two-way ANOVA; all test details can be found online (https://doi.org/10.18710/LUAHFK), before falling back to SP levels 23 h after lights on (CT 23).…”

Section: In Briefmentioning

confidence: 99%

Evidence for circadian-based photoperiodic timekeeping in Svalbard ptarmigan, the northernmost resident bird

et al. 2021

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“…In temperate and tropical bird species [18][19][20][21][22][23] the seasonal reproductive response depends on photoperiodic control of thyrotropin beta subunit (Tshβ) expression in the PT and consequent thyrotropin receptor-mediated changes in MBH function, exemplified by changes in the expression of the thyroid hormone deiodinase genes, Dio2 and Dio3. In the Svalbard ptarmigan Tshβ expression in the PT was continuously suppressed under SP, and transfer to LL strongly induced Tshβ expression, which peaked 13 h after lights-on (CT13) (p < 0.0001 compared to SP control birds by Sidak's post hoc test) ( Figure 1E) before falling back to SP levels by 23 h after lights-on (CT23).…”

Section: The Rhythmic Expression Of Circadian Clock Genes In the Medimentioning

confidence: 99%

Adaptive value of circadian rhythms in High Arctic Svalbard ptarmigan

Appenroth

Wagner

Hazlerigg

et al. 2020

Preprint

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The arctic archipelago of Svalbard (74 to 81 degrees North) experiences extended periods of uninterrupted daylight in summer and uninterrupted darkness in winter. Species native to Svalbard display no daily rhythms in behaviour or physiology during these seasons, leading to the view that circadian rhythms may be redundant in arctic environments. Nevertheless, seasonal changes in the physiology and behaviour of arctic species rely on photoperiodic synchronisation to the solar year. Since this phenomenon is generally circadian-based in temperate species, we investigated if this might be a preserved aspect of arctic temporal organisation. Here, we demonstrate the involvement of the circadian clock in the seasonal photoperiodic response of the Svalbard ptarmigan (Lagopus muta hyperborea), the world's northernmost resident bird species. First, we show the persistence of rhythmic clock gene expression under constant conditions within the mediobasal hypothalamus and pars tuberalis, the key tissues in the seasonal neuroendocrine cascade. We then employ a sliding skeleton photoperiod protocol, revealing that the driving force behind seasonal biology of the Svalbard ptarmigan is rhythmic sensitivity to light, a feature that depends on a functioning circadian rhythm. Our results suggest that the unusual selective pressure of the Arctic relaxes the adaptive value of the circadian clock for organisation of daily activity patterns, whilst preserving its importance for seasonal synchronisation. Thus, our data simultaneously reconnects circadian rhythms to life in the Arctic and establishes a universal principle of evolutionary value for circadian rhythms in seasonal biology.

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Molecular basis of photoperiodic control of reproductive cycle in a subtropical songbird, the Indian weaver bird (Ploceus philippinus)

Cited by 9 publications

References 30 publications

Seasonally sympatric but allochronic: differential expression of hypothalamic genes in a songbird during gonadal development

Seasonally sympatric but allochronic: differential expression of hypothalamic genes in a songbird during gonadal development

Evidence for circadian-based photoperiodic timekeeping in Svalbard ptarmigan, the northernmost resident bird

Adaptive value of circadian rhythms in High Arctic Svalbard ptarmigan

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