MERILÄ LAB

Research and Discoveries

Current Areas of Research:

 

Get in touch to learn more about our research.

 
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MUTATION RATES IN LARGE AND SMALL POPULATIONS

In collaboration with Prof. Mikkel Schierup (Aarhus University)

Mutations are the ultimate source of genetic variation, but with the exception of few model species, we still know little about de novo mutation rates in the wild, how much intraspecific variation there is in mutation rates, and what ultimately determines large difference in mutation rates among different species and populations. The drift-barrier hypothesis posits that the species effective population size is an important determinant of mutation rate: since most mutations are harmful and selected against, and because selection is more efficient in large than in small populations, drift in small populations renders them prone to increased mutation rates. However, since estimation of mutation rates is challenging, very little is known about intraspecific variability in mutation rates, and tests of the drift-barrier hypothesis at intraspecific level are missing. Our aim is to obtain accurate estimates de novo mutation rates from multiple stickleback populations differing dramatically in the amount genetic drift they have experienced and test if there is a negative relationship between mutation rate and effective population size as predicted by the drift-barrier hypothesis.

RESEARCH IN HELSINKI

Current Areas of Study

After moving to HK, my research group in Helsinki continues pursue their work under my mentorship

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DETERMINANTS OF GENETIC DIVERSITY & RECOMBINATION RATE VARIATION

MSc Mikko Kivikoski, MSc Xeuyun Feng, Dr. Ari Löytynoja, Dr. Pasi Rastas, Dr. Antoine Fraimout

We have discovered that the range genetic diversities across ca 50 nine-spined stickleback populations span a range several orders of magnitude, the genetically most depaurate population having less nucleotide diversity than Gorillas, Channel Island Foxes and Cheetahs. Since the life history differences among different stickleback populations are small, we believe that the range of intraspecific variation in nucleotide diversity we see is strong testimony of population demography as a determinant of genetic diversity

FACTORS INFLUENCING LIKELIHOOD OF PARALLEL EVOLUTION

Dr. Petri Kemppainen, Dr. Bohao Fang, Dr. Paolo Momigliano, MSc. Xueyun Feng, Dr. Ari Löytynoja, MSc Caral Costa, MSc Carolin Dahms

Our studies in parallel evolution continues using sticklebacks as model systems. We are currently looking into genetic genetic parallelism in freshwater populations nine-spined sticklebacks using whole genome seuquence data, and also studying genetic parallelism in three-spined sticklebacks in systems where the ancestral marine population does not anymore exist.

SPECIATION AND LOCAL ADAPTATION IN FLATFISHES

Dr. Paolo Momigliano and MSc Thais Ferreira-Araújo

Using different flatfish species as models, we continue to explore the genomic underpinnings of adaptive differentiation and speciation in flatfishes. Of our particular interest is a freshwater dwelling European flatfish (Platichtys floss) population in Lake Pulmanki in Northern Finland. Stable isotope analyses of otolith micro-chemistry indicate that the flounders in this lake consist of both freshwater and brackish water born individuals. The quest is on to figure out if marine flounders have adapted to freshwater reproduction and possibly spectated to be a distinct species.

 
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QUANTITATIVE GENOMICS

With Dr. Antoine Fraimout

Many questions in evolutionary biology require information about the genetic basis and inheritance of traits under study. This information is not easy obtain. We have been exploring the utility of identity by descent relationships among full-sibs as short cut to estimate trait heritabilities in multiple wild populations using sticklebacks as model system. All the experimental work has been finalised - watch out this space for news.

ANIMAL RESPONSES TO WARMING CLIMATE

With Dr. Emma Vatka, Prof Markku Orell, dr. Kari Koivula

The focus of this project is in understanding how boreal zone birds respond to warming climatic conditions. The study is based over 50 year time-series of individually marked Great Tits (Parus major) and Willow Tits (Parus montanus) collected from northern Finland.

RESOLVING THE RAPID ANCIENT RADIATION OF ELAPOIDS

MSc Sunandan Das

Snake superfamily Elapoidea includes diverse types of snakes, from unusual, rare, back-fanged snakes from central African impenetrable rainforests to the mighty King Cobra of Asia and the deadly Black Mamba of Africa. However, the higher-level phylogeny of elapoids has proven to be a challenge for evolutionary biologists as they diversified very rapidly in the early Cenozoic. Sunandan is inferring the phylogeny of elapoids using ultraconserved elements and studying their skulls to pick up tell-tale signs of the possible trajectory of elapoid evolution.