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Ljungström G, Stjernstedt M, Wapstra E, Olsson M. Selection and constraints on offspring size-number trade-offs in sand lizards (Lacerta agilis). J Evol Biol 2016; 29:979-90. [PMID: 26851437 DOI: 10.1111/jeb.12838] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 01/25/2016] [Accepted: 01/31/2016] [Indexed: 11/27/2022]
Abstract
The trade-off between offspring size and number is a central component of life-history theory, postulating that larger investment into offspring size inevitably decreases offspring number. This trade-off is generally discussed in terms of genetic, physiological or morphological constraints; however, as among-individual differences can mask individual trade-offs, the underlying mechanisms may be difficult to reveal. In this study, we use multivariate analyses to investigate whether there is a trade-off between offspring size and number in a population of sand lizards by separating among- and within-individual patterns using a 15-year data set collected in the wild. We also explore the ecological and evolutionary causes and consequences of this trade-off by investigating how a female's resource (condition)- vs. age-related size (snout-vent length) influences her investment into offspring size vs. number (OSN), whether these traits are heritable and under selection and whether the OSN trade-off has a genetic component. We found a negative correlation between offspring size and number within individual females and physical constraints (size of body cavity) appear to limit the number of eggs that a female can produce. This suggests that the OSN trade-off occurs due to resource constraints as a female continues to grow throughout life and, thus, produces larger clutches. In contrast to the assumptions of classic OSN theory, we did not detect selection on offspring size; however, there was directional selection for larger clutch sizes. The repeatabilities of both offspring size and number were low and we did not detect any additive genetic variance in either trait. This could be due to strong selection (past or current) on these life-history traits, or to insufficient statistical power to detect significant additive genetic effects. Overall, the findings of this study are an important illustration of how analyses of within-individual patterns can reveal trade-offs and their underlying causes, with potential evolutionary and ecological consequences that are otherwise hidden by among-individual variation.
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Affiliation(s)
- G Ljungström
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - M Stjernstedt
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
| | - E Wapstra
- School of Biological Sciences, University of Tasmania, Hobart, Tas., Australia
| | - M Olsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.,School of Biological Sciences, University of Sydney, Sydney, NSW, Australia
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Matsubara K, Uno Y, Srikulnath K, Matsuda Y, Miller E, Olsson M. No Interstitial Telomeres on Autosomes but Remarkable Amplification of Telomeric Repeats on the W Sex Chromosome in the Sand Lizard (Lacerta agilis). ACTA ACUST UNITED AC 2015; 106:753-7. [PMID: 26464091 DOI: 10.1093/jhered/esv083] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 09/25/2015] [Indexed: 11/13/2022]
Abstract
Telomeres are repeat (TTAGGG) n sequences that form terminal ends of chromosomes and have several functions, such as protecting the coding DNA from erosion at mitosis. Due to chromosomal rearrangements through evolutionary history (e.g., inversions and fusions), telomeric sequences are also found between the centromere and the terminal ends (i.e., at interstitial telomeric sites, ITSs). ITS telomere sequences have been implicated in heritable disease caused by genomic instability of ITS polymorphic variants, both with respect to copy number and sequence. In the sand lizard (Lacerta agilis), we have shown that telomere length is predictive of lifetime fitness in females but not males. To assess whether this sex specific fitness effect could be traced to ITSs differences, we mapped (TTAGGG) n sequences using fluorescence in situ hybridization in fibroblast cells cultured from 4 specimens of known sex. No ITSs could be found on autosomes in either sex. However, females have heterogametic sex chromosomes in sand lizards (ZW, 2n = 38) and the female W chromosome showed degeneration and remarkable (TTAGGG) n amplification, which was absent in the Z chromosomes. This work warrants further research on sex chromosome content, in particular of the degenerate W chromosome, and links to female fitness in sand lizards.
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Affiliation(s)
- Kazumi Matsubara
- From the Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan (Matsubara, Uno, Srikulnath, and Matsuda); Department of Information and Biological Sciences, Graduate School of Natural Sciences, Nagoya City University, Nagoya, Japan (Matsubara); Laboratory of Animal Cytogenetics & Comparative Genomics, Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand (Srikulnath); Avian Bioscience Research Center, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan (Matsuda); Sydney Medical School QEII Research Institute for Mothers and Infants D02, The University of Sydney , NSW 2006, Australia (Miller); School of Biological Sciences, The University of Sydney, Heydon-Laurence Building A08, NSW 2006, Australia (Olsson); and Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden (Olsson)
| | - Yoshinobu Uno
- From the Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan (Matsubara, Uno, Srikulnath, and Matsuda); Department of Information and Biological Sciences, Graduate School of Natural Sciences, Nagoya City University, Nagoya, Japan (Matsubara); Laboratory of Animal Cytogenetics & Comparative Genomics, Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand (Srikulnath); Avian Bioscience Research Center, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan (Matsuda); Sydney Medical School QEII Research Institute for Mothers and Infants D02, The University of Sydney , NSW 2006, Australia (Miller); School of Biological Sciences, The University of Sydney, Heydon-Laurence Building A08, NSW 2006, Australia (Olsson); and Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden (Olsson)
| | - Kornsorn Srikulnath
- From the Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan (Matsubara, Uno, Srikulnath, and Matsuda); Department of Information and Biological Sciences, Graduate School of Natural Sciences, Nagoya City University, Nagoya, Japan (Matsubara); Laboratory of Animal Cytogenetics & Comparative Genomics, Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand (Srikulnath); Avian Bioscience Research Center, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan (Matsuda); Sydney Medical School QEII Research Institute for Mothers and Infants D02, The University of Sydney , NSW 2006, Australia (Miller); School of Biological Sciences, The University of Sydney, Heydon-Laurence Building A08, NSW 2006, Australia (Olsson); and Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden (Olsson)
| | - Yoichi Matsuda
- From the Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan (Matsubara, Uno, Srikulnath, and Matsuda); Department of Information and Biological Sciences, Graduate School of Natural Sciences, Nagoya City University, Nagoya, Japan (Matsubara); Laboratory of Animal Cytogenetics & Comparative Genomics, Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand (Srikulnath); Avian Bioscience Research Center, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan (Matsuda); Sydney Medical School QEII Research Institute for Mothers and Infants D02, The University of Sydney , NSW 2006, Australia (Miller); School of Biological Sciences, The University of Sydney, Heydon-Laurence Building A08, NSW 2006, Australia (Olsson); and Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden (Olsson)
| | - Emily Miller
- From the Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan (Matsubara, Uno, Srikulnath, and Matsuda); Department of Information and Biological Sciences, Graduate School of Natural Sciences, Nagoya City University, Nagoya, Japan (Matsubara); Laboratory of Animal Cytogenetics & Comparative Genomics, Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand (Srikulnath); Avian Bioscience Research Center, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan (Matsuda); Sydney Medical School QEII Research Institute for Mothers and Infants D02, The University of Sydney , NSW 2006, Australia (Miller); School of Biological Sciences, The University of Sydney, Heydon-Laurence Building A08, NSW 2006, Australia (Olsson); and Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden (Olsson)
| | - Mats Olsson
- From the Laboratory of Animal Genetics, Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan (Matsubara, Uno, Srikulnath, and Matsuda); Department of Information and Biological Sciences, Graduate School of Natural Sciences, Nagoya City University, Nagoya, Japan (Matsubara); Laboratory of Animal Cytogenetics & Comparative Genomics, Department of Genetics, Faculty of Science, Kasetsart University, Bangkok, Thailand (Srikulnath); Avian Bioscience Research Center, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan (Matsuda); Sydney Medical School QEII Research Institute for Mothers and Infants D02, The University of Sydney , NSW 2006, Australia (Miller); School of Biological Sciences, The University of Sydney, Heydon-Laurence Building A08, NSW 2006, Australia (Olsson); and Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden (Olsson).
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Olsson M, Stuart-Fox D, Ballen C. Genetics and evolution of colour patterns in reptiles. Semin Cell Dev Biol 2013; 24:529-41. [PMID: 23578866 DOI: 10.1016/j.semcdb.2013.04.001] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 04/02/2013] [Indexed: 10/27/2022]
Abstract
The study of coloration in the polyphyletic reptilians has flourished in the last two decades, in particular with respect to the underlying genetics of colour traits, the function of colours in social interactions, and ongoing selection on these traits in the wild. The taxonomic bias, however, is profound: at this level of resolution almost all available information is for diurnal lizards. Therefore, we focus on case studies, for which there are as complete causal sequences of colour evolution as possible, from phenotypic expression of variation in colour, to ongoing selection in the wild. For work prior to 1992 and for a broader coverage of reptilian coloration we refer the readers to Cooper and Greenburg's (Biology of the Reptilia, 1992) review. There are seven major conclusions we would like to emphasise: (a) visual systems in diurnal lizards are broadly conserved but among the wider range of reptiles in general, there is functionally important variation in the number and type of photoreceptors, spectral tuning of photopigments and optical properties of the eye; (b) coloration in reptiles is a function of complex interactions between structural and pigmentary components, with implications for both proximate control and condition dependence of colour expression; (c) studies of colour-variable species have enabled estimates of heritability of colour and colour patterns, which often show a simple Mendelian pattern of inheritance; (d) colour-polymorphic lizard species sometimes, but not always, show striking differences in genetically encoded reproductive tactics and provide useful models for studying the evolution and maintenance of polymorphism; (e) both male and female colours are sometimes, but not always, a significant component of socio-sexual signalling, often based on multiple traits; (f) evidence for effects of hormones and condition on colour expression, and trade-offs with immunocompetence and parasite load, is variable; (g) lizards show fading of colours in response to physiological stress and ageing and are hence likely to be appropriate models for work on the interactions between handicaps, indicator traits, parasitology and immunoecology.
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Affiliation(s)
- Mats Olsson
- School of Biological Sciences, University of Sydney, Sydney, NSW 2006, Australia.
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