| 1. |
- Chase, Madeline, et al.
(författare)
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The combination of HiFi and HiC sequencing technologies enables the investigation of structural variants in speciation of Ficedula flycatchers
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Structural variants, typically defined as mutations affecting more than 50bp, have been shown to encompass a significant portion of the genome and can have large phenotypic effects. Additionally, increasing empirical evidence demonstrates that structural variants may play a substantial role in speciation, which could previously have been overlooked because of difficulties in identifying them with short-read data. However, with the increased availability of long-read sequencing technology we are now equipped better than ever to address this limitation and study the contribution of different types of structural variants to genetic variation within and genetic differentiation between closely related species. Here, we follow this approach and combine PacBio HiFi and HiC sequencing for two closely related passerine birds, the collared flycatcher and the pied flycatcher. This enables us to generate a chromosome-level genome assembly for both species, and identify structural variants between the two species. Based on population-level HiFi sequencing for both species, we then investigate patterns of single nucleotide diversity and differentiation within and between species and their association with different types of structural variation. We find widespread structural variation between the two species, where both the sex chromosomes show a disproportionate number of structural variants, which may help explain the suspected role of the Z-chromosome in contributing to genetic incompatibilities. We also find that genomic differentiation peaks are enriched in both translocations and inversions, which supports a mechanistic role of structural variation in population differentiation and speciation.
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| 2. |
- Crino, Ondi L., et al.
(författare)
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Mitochondria as the powerhouses of sexual selection : Testing mechanistic links between development, cellular respiration, and bird song
- 2022
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Ingår i: Hormones and Behavior. - : Elsevier BV. - 0018-506X .- 1095-6867. ; 142
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Tidskriftsartikel (refereegranskat)abstract
- The developmental environment can affect the expression of sexually selected traits in adulthood. The physiological mechanisms that modulate such effects remain a matter of intense debate. Here, we test the role of the developmental environment in shaping adult mitochondrial function and link mitochondrial function to expression of a sexually selected trait in males (bird song). We exposed male zebra finches (Taeniopygia guttata) to corticosterone (CORT) treatment during development. After males reached adulthood, we quantified mitochondrial function from whole red blood cells and measured baseline CORT and testosterone levels, body condition/composition, and song structure. CORT-treated males had mitochondria that were less efficient (FCRL/R) and used a lower proportion of maximum capacity (FCRR/ETS) than control males. Additionally, CORT-treated males had higher baseline levels of CORT as adults compared to control males. Using structural equation modelling, we found that the effects of CORT treatment during development on adult mitochondrial function were indirect and modulated by baseline CORT levels, which are programmed by CORT treatment during development. Developmental treatment also had an indirect effect on song peak frequency. Males treated with CORT during development sang songs with higher peak frequency than control males, but this effect was modulated through increased CORT levels and by a decrease in FCRR/ETS. CORT-treated males had smaller tarsi compared to control males; however, there were no associations between body size and measures of song frequency. Here, we provide the first evidence supporting links between the developmental environment, mitochondrial function, and the expression of a sexually selected trait (bird song).
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| 3. |
- Kraft, Fanny-Linn H., et al.
(författare)
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Developmental conditions have intergenerational effects on corticosterone levels in a passerine
- 2021
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Ingår i: Hormones and Behavior. - : Elsevier BV. - 0018-506X .- 1095-6867. ; 134
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Tidskriftsartikel (refereegranskat)abstract
- The developmental environment can have powerful, canalizing effects that last throughout an animal's life and even across generations. Intergenerational effects of early-life conditions may affect offspring phenotype through changes in the hypothalamic-pituitary-adrenal axis (HPA). However, such effects remain largely untested in altricial birds. Here, we tested the impact of maternal and paternal developmental conditions on offspring physiology and morphology in the zebra finch (Taeniopygia guttata). Specifically, we exposed one generation (F1) to elevated corticosterone (CORT) during development and quantified the impact on offspring (F2) phenotype. We predicted that intergenerational effects would be apparent through effects of parental developmental treatment on offspring body mass, growth, body condition, body composition, and CORT levels. We found an intergenerational impact on CORT levels, such that F2 birds reared by CORT-treated fathers had higher baseline CORT than F2 birds reared by control fathers. This result shows the potential for intergenerational effects on endocrine function, resulting from developmental conditions. We found no effect of parental treatment on F2 body mass, size, or body condition, but we found that the body mass and tarsus length for offspring and parent were correlated. Our study demonstrates the subtle effects of developmental conditions across generations and highlights the importance of distinguishing between maternal and paternal effects when studying intergenerational effects, especially for species with biparental care.
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| 4. |
- Kraft, Fanny Linn, et al.
(författare)
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No evidence for self-recognition in a small passerine, the great tit (Parus major) judged from the mark/mirror test
- 2017
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Ingår i: Animal Cognition. - : Springer Science and Business Media LLC. - 1435-9448 .- 1435-9456. ; 20:6, s. 1049-1057
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Tidskriftsartikel (refereegranskat)abstract
- Self-recognition is a trait presumed to be associated with high levels of cognition and something previously considered to be exclusive to humans and possibly apes. The most common test of self-recognition is the mark/mirror test of whether an animal can understand that it sees its own reflection in a mirror. The usual design is that an animal is marked with a colour spot somewhere on the body where the spot can only be seen by the animal by using a mirror. Very few species have passed this test, and among birds, only magpies have been affirmatively demonstrated to pass it. In this study, we tested great tits (Parus major), small passerines, that are known for their innovative foraging skills and good problem-solving abilities, in the mirror self-recognition test. We found no indication that they have any ability of this kind and believe that they are unlikely to be capable of this type of self-recognition.
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| 5. |
- Wheatcroft, David, et al.
(författare)
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Species-specific song responses emerge as a by-product of tuning to the local dialect
- 2022
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 32:23, s. 5153-5158, 5153–5158.e1–e5
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Tidskriftsartikel (refereegranskat)abstract
- Oscine birds preferentially respond to certain sounds over others from an early age, which focuses subsequent learning onto sexually relevant songs. Songs vary both across species and, due to cultural evolution, among populations of the same species. As a result, early song responses are expected to be shaped by selection both to avoid the fitness costs of cross-species learning and to promote learning of population-typical songs. These sources of selection are not mutually exclusive but can result in distinct geographic patterns of song responses in juvenile birds: if the risks of interspecific mating are the main driver of early song discrimination, then discrimination should be strongest where closely related species co-occur. In contrast, if early discrimination primarily facilitates learning local songs, then it should be tuned to songs typical of the local dialect. Here, we experimentally assess the drivers of song discrimination in nestling pied flycatchers (Ficedula hypoleuca). We first demonstrate that early discrimination against the songs of the closely related collared flycatcher (F. albicollis) is not strongly affected by co-occurrence. Second, across six European populations, we show that nestlings’ early song responses are tuned to their local song dialect and that responses to the songs of collared flycatchers are similarly weak as to those of other conspecific dialects. Taken together, these findings provide clear experimental support for the hypothesis that cultural evolution, in conjunction with associated learning predispositions, drives the emergence of pre-mating reproductive barriers.
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