Fine-tuning of seasonal timing of breeding is regulated downstream in the underlying neuro-endocrine system in a small songbird

TY - JOUR

T1 - Fine-tuning of seasonal timing of breeding is regulated downstream in the underlying neuro-endocrine system in a small songbird

AU - Verhagen, Irene

AU - Laine, Veronika N.

AU - Mateman, A. Christa

AU - Pijl, Agata

AU - de Wit, Ruben

AU - van Lith, Bart

AU - Kamphuis, Willem

AU - Viitaniemi, Heidi M.

AU - Williams, Tony D.

AU - Caro, Samuel P.

AU - Meddle, Simone L.

AU - Gienapp, Phillip

AU - van Oers, Kees

AU - Visser, Marcel E.

N1 - 6799, AnE; Data archiving: data archived in Dataverse

PY - 2019

Y1 - 2019

N2 - Timing of breeding is under selection in wild populations due to climate change, and understanding the underlying physiological processes mediating timing provides insight in the potential rate of adaptation. Current knowledge on this variation in physiology is, however, mostly limited to males. We assessed whether individual differences in timing of breeding in females are reflected in differences in candidate gene expression and if so, whether these differences occur in the upstream (hypothalamus), or downstream (ovary and liver) parts of the neuroendocrine system. We used 72 female great tits from two generations of lines artificially selected for early and late egg-laying, which were housed in climate controlled aviaries and went through two breeding cycles within one year. In the first breeding season we obtained individual egg-laying dates, while in the second breeding season, using the same individuals, we sampled several tissues at three time points based on timing of the first breeding attempt. For each tissue, mRNA expression levels were measured using qPCR for a set of candidate genes associated with timing of reproduction and subsequently analysed for differences between generations, time points and individual timing of breeding. We found differences in gene expression between generations in all tissues with most pronounced differences in the hypothalamus. Differences between time points, and early and late laying females, were found exclusively in ovary and liver. Altogether, we show that fine-tuning of seasonal timing of breeding, and thereby the opportunity for adaptation in the neuroendocrine system, is regulated mostly downstream in the neuro-endocrine system.

AB - Timing of breeding is under selection in wild populations due to climate change, and understanding the underlying physiological processes mediating timing provides insight in the potential rate of adaptation. Current knowledge on this variation in physiology is, however, mostly limited to males. We assessed whether individual differences in timing of breeding in females are reflected in differences in candidate gene expression and if so, whether these differences occur in the upstream (hypothalamus), or downstream (ovary and liver) parts of the neuroendocrine system. We used 72 female great tits from two generations of lines artificially selected for early and late egg-laying, which were housed in climate controlled aviaries and went through two breeding cycles within one year. In the first breeding season we obtained individual egg-laying dates, while in the second breeding season, using the same individuals, we sampled several tissues at three time points based on timing of the first breeding attempt. For each tissue, mRNA expression levels were measured using qPCR for a set of candidate genes associated with timing of reproduction and subsequently analysed for differences between generations, time points and individual timing of breeding. We found differences in gene expression between generations in all tissues with most pronounced differences in the hypothalamus. Differences between time points, and early and late laying females, were found exclusively in ovary and liver. Altogether, we show that fine-tuning of seasonal timing of breeding, and thereby the opportunity for adaptation in the neuroendocrine system, is regulated mostly downstream in the neuro-endocrine system.

KW - international

UR - https://hdl.handle.net/10411/5CQPHI

U2 - 10.1242/jeb.202481

DO - 10.1242/jeb.202481

M3 - Article

SN - 0022-0949

VL - 222

JO - Journal of Experimental Biology

JF - Journal of Experimental Biology

M1 - jeb.202481

ER -