Pirmin Nietlisbach

I am an evolutionary biologist interested in evolutionary and conservation genetics and genomics. The central theme of my research is investigating the causes and consequences of patterns of genetic variation, an essential component of biodiversity. Genetic variation is of key importance in evolutionary biology, because genetic variation forms the basis for evolution to act on. I use a variety of methods ranging from data collection in the field, genetic and genomic analysis, computer simulations, theory, and statistical approaches. Below are summaries of the projects I have been working on.

 

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Inbreeding and genetics in song sparrows

 

A lot of my recent work focused on a fundamental topic in evolutionary biology: inbreeding. I studied the extent to which fitness variation is affected by inbreeding and heterozygosity in song sparrows (Melospiza melodia). I used 160 microsatellite markers to reconstruct a genetic pedigree and a linkage map, and to describe chromosomal rearrangements between song sparrows and zebra finches (Taeniopygia guttata). Pedigree-based inbreeding coefficients explained more variation in fitness than heterozygosity at 160 loci, which helped to better understand the use of genetic markers or pedigrees as measures of identity by descent. Collaborators have led a number of other investigations on extra-pair paternity, fitness, or sperm performance.

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Publications:

 

Reid, J. M., Keller, L. F., Marr, A. B., Nietlisbach, P., Sardell, R. J., Arcese, P. (2014): Pedigree error due to extrapair reproduction substantially biases estimates of inbreeding depression. Evolution 68: 802-815.

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Reid, J. M., Arcese, P., Keller, L. F., Germain, R. R., Duthie, A. B., Losdat, S., Wolak, M. E., Nietlisbach, P. (2015): Quantifying inbreeding avoidance through extra-pair reproduction. Evolution 69: 59-74.

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Nietlisbach, P., Camenisch, G., Bucher, T., Slate, J., Keller, L. F., Postma, E. (2015): A microsatellite-based linkage map for song sparrows (Melospiza melodia). Molecular Ecology Resources 15: 1486-1496.

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Reid, J. M., Bocedi, G., Nietlisbach, P., Duthie, A. B., Wolak, M. E., Gow, E. A., Arcese, P. (2016): Variation in parent-offspring kinship in socially monogamous systems with extra-pair reproduction and inbreeding. Evolution 70: 1512-1529.

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Nietlisbach, P., Keller, L. F., Camenisch, G., Guillaume, F., Arcese, P., Reid, J. M., Postma, E. (2017): Pedigree-based inbreeding coefficient explains more variation in fitness than heterozygosity at 160 microsatellites in a wild bird population. Proceedings of the Royal Society B 284: 20162763.

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Losdat, S., Germain, R. R., Nietlisbach, P., Arcese, P., Reid, J. M. (2018): No evidence of inbreeding depression in sperm performance traits in wild song sparrows. Ecology and Evolution 8: 1842-1852.

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Wolak, M. E., Arcese, P., Keller, L. F., Nietlisbach, P., Reid, J. M. (2018): Sex-specific additive genetic variances and correlations for fitness and fitness components in a song sparrow (Melospiza melodia) population subject to natural immigration and inbreeding. Evolution 72: 2057-2075.

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Reid, J. M., Nietlisbach, P., Wolak, M. E., Keller, L. F., Arcese, P. (2019): Individuals’ expected genetic contributions to future generations, reproductive value, and short-term metrics of fitness in free-living song sparrows (Melospiza melodia). Evolution Letters 3: 271-285.

 

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Methods to estimate inbreeding load

 

Genetically explicit simulations of survival and of genomic and pedigree-based metrics of inbreeding show how to get comparable estimates of inbreeding load. Such estimates are important in conservation genetics and evolutionary biology.

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Publications:

 

Kardos, M., Nietlisbach, P., Hedrick, P. (2018): How should we compare different genomic estimates of the strength of inbreeding depression? Proceedings of the National Academy of Sciences 115: E2492-E2493.

 

Nietlisbach, P., Muff, S., Reid, J. M., Whitlock, M., Keller, L. F. (2019): Nonequivalent lethal equivalents: Models and inbreeding metrics for unbiased estimation of inbreeding load. Evolutionary Applications 12: 266-279.

 

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Heritability of heterozygosity

 

I used quantitative genetics to develop theoretical expectations of the heritability of heterozygosity, and thereby developed the first framework that allowed to predict the heritability of heterozygosity for genetic loci with more than two alleles and inbreeding. This also paved the ground for providing an intuitively understandable and theoretically supported explanation for why dominant gene action contributes to additive genetic variance, an important quantity in quantitative genetics.

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Publications:

 

Nietlisbach, P., Keller, L. F., Postma, E. (2016): Genetic variance components and heritability of multiallelic heterozygosity under inbreeding. Heredity 116: 1-11.

 

Nietlisbach, P., Hadfield, J. D. (2015): Heritability of heterozygosity offers a new way of understanding why dominant gene action contributes to additive genetic variance. Evolution 69: 1948-1952.

 

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Galápagos mockingbird phylogeny

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I conducted a phylogenetic study on Galápagos mockingbirds (Mimus spp.) that unveiled discordant patterns of mitochondrial and nuclear genetic variation in the population on Genovesa Island. This result suggests that this population experienced hybridization between two species from other islands.

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Publication:

 

Nietlisbach, P., Wandeler, P., Parker, P. G., Grant, P. R., Grant, B. R., Keller, L. F., Hoeck, P. E. A. (2013): Hybrid ancestry of an island subspecies of Galápagos mockingbird explains discordant gene trees. Molecular Phylogenetics and Evolution 69: 581-592.

 

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Sex-biased dispersal in orang-utans

 

Geographic patterns in genetic variation provide information about dispersal strategies, which are important in evolutionary and behavioral ecology. For my MSc thesis, I developed male-specific markers for orang-utans (Pongo spp.) in order to measure Y-chromosomal and mitochondrial genetic diversity across a large set of orang-utan individuals from wild populations on Borneo and Sumatra. These data showed for the first time unequivocally that orang-utan dispersal is strongly male-biased. Signatures of male-biased dispersal were also evident from comparing phylogenies for different sex-linked genetic markers.

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Publications:

 

Arora, N., van Noordwijk, M. A. , Ackermann, C., Willems, E. P., Nater, A., Greminger, M., Nietlisbach, P., Dunkel, L. P., Utami Atmoko, S. S., Pamungkas, J., Perwitasari-Farajallah, D., van Schaik, C. P., Krützen, M. (2012): Parentage-based pedigree reconstruction reveals female matrilineal clusters and male-biased dispersal in nongregarious Asian great apes, the Bornean orang-utans (Pongo pygmaeus). Molecular Ecology 21: 3352-3362.

 

Nietlisbach, P., Arora, N., Nater, A., Goossens, B., van Schaik, C. P., Krützen, M. (2012): Heavily male-biased long-distance dispersal of orang-utans (genus: Pongo), as revealed by Y-chromosomal and mitochondrial genetic markers. Molecular Ecology 21: 3173-3186.

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Nater, A., Nietlisbach, P., Arora, N., van Schaik, C. P., van Noordwijk, M. A., Willems, E. P., Singleton, I., Wich, S. A., Goossens, B., Warren, K., Verschoor, E., Perwitasari-Farajallah, D., Pamungkas, J., Krützen, M. (2011): Sex-biased dispersal and volcanic activities shaped phylogeographic patterns of extant orangutans (genus: Pongo). Molecular Biology and Evolution 28: 2275-2288.

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Nietlisbach, P., Nater, A., Greminger, M. P., Arora, N., Krützen, M. (2010): A multiplex system to target 16 male-specific and 15 autosomal genetic markers for orang-utans (genus: Pongo). Conservation Genetics Resources 2: 153-158.

 

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Natural history observations

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As a passionate birdwatcher and observer of nature, I also enjoy documenting fascinating events in nature.

 

Publication:

 

Nietlisbach, P., Germain, R. R., Bousquet, C. A. H. (2014): Observations of Glaucous-winged Gulls preying on passerines at a Pacific Northwest colony. The Wilson Journal of Ornithology 126: 155-158.