Researchers from Biotech Research & Innovation Centre (BRIC) at University of Copenhagen have now identified a gene-family that is essential for regulating the differentiation potential of stem cells and normal development. The results are published in the current issue of Cell.

How stem cells work

All living organisms, including human beings, consist of a number of specialised cell types that all originate from the same type of primal cell; the embryonic stem cell. Stem cells can develop into any type of cell through a carefully regulated process referred to as cellular differentiation. During differentiation, specific genes are switched on while other genes are switched off. The genes that are activated during differentiation determine which type of cell the stem cell will become. The result is that cells in a particular organ, e.g. a liver, only express genes specific to that organ.

What the research showed

Director of BRIC, Professor Kristian Helin led the research team consisting of Jesper Christensen, Karl Agger and Paul Cloos. Last year, the same research group published an article in Nature on how a group of Jumonji proteins regulate the growth of cancer cells and are involved in the development of specific cancer types.

BRIC’s new results show that a different subgroup of Jumonji proteins is essential for cellular differentiation. The Jumonji enzymes can turn off, or inactivate, particular genes that play an important part in embryogenesis. The conclusions are based on studies of the nematode (roundworm) C. elegans and studies of mouse embryonic stem cells. The C. elegans studies were carried out in collaboration with another of BRIC’s research groups, led by Associate Professor Lisa Salcini.

How can the results be used?

The BRIC researchers are currently developing inhibitors to the Jumonji proteins. Their aim is to use these inhibitors to treat cancer patients with increased levels of the Jumonji proteins.

Contact: Professor Kristian Helin, phone: +45 35 32 56 66 / e-mail: kristian.helin @ bric.dk

The ability for some animals to have live births versus eggs can normally be explained by what classification the animal belongs to.

Mammals have live births, birds have eggs, Echidnas (a relative of mammals, think platypus) have eggs (like birds) but also have some characteristics only seen in mammals (fur and milk for their young).

There are some classification of animals that can have either live birth or eggs, such as sharks, fish and some reptiles.

The difference between the whether there are live births versus eggs is usually determined by the environment.

What caused the extinction of the mammoth while other ice age mammals like the musk ox survived to present day? A new scientific methodological approach to detect genetic material will help researchers to solve the many mysteries of the past.

“I’m confident that the new methodological approach, will be of great importance to molecular biology”, says Professor Eske Willerslev at the Centre for Ancient Genetics, University of Copenhagen. One of his PhD students recently came up with a brilliant idea enabling researchers to get a full view of total ecosystems or populations dating thousands of years back in time. What usually has taken the DNA-researchers several years of laboratory work can now be done in just a few hours.

The automation of a long research process

Professor Eske Willerslev and his team find DNA traces of ancient life in areas where the ground is permanently frozen like in Siberia or Alaska. Here, inside the frozen ground, the team is able to find ancient DNA material from animals and plants that used to live in the area thousands of years ago. In order to detect the types of DNA material in a sample, the researchers normally use a DNA primer – a kind of ‘fishing hook’ attached to a specific piece of DNA. That particular piece of DNA is then being multiplied, cloned and sequenced which makes it possible for the researchers to identify it. However, this procedure is slow, and it takes years just to identify a fraction of the most common animals and plants available from the many DNA samples.

The technology

A new sequencing machine capable of interpreting millions of pieces of DNA in just a few hours was recently introduced. The machine alone brought in a revolution to the field, but has certain disadvantages and shortcomings. Firstly, an analysis made by the machine is quite expensive. Each analysis costs approximately DKK 45,000 and although the machine reads extensive amounts of DNA material, the cost is still considerable to a research project. Secondly, a vital problem arises when researchers try to benefit from the machine’s enormous capacity by analysing samples from multiple locations or specimens in a single run in order to reduce costs. The machine simply cannot separate more than 16 samples from each other.

Eske Willerslev went to check out the machine for himself at the Danish Cattle Research Centre in Foulum – the only place in Denmark, which operates the new sequencing machine. He realised to his great disappointment that the researchers at the University of Copenhagen could not make use of the machine for their respective projects due to the disadvantages mentioned above.

A simple but brilliant idea!

Then Jonas Binladen, a PhD student from his team, came up with a simple but brilliant idea: By attaching a ‘finger-print’ to the tagged primers (‘fishing hooks’ used to amplify DNA from each sample), one should – in theory – be able to localise each of the million sequences produced in each run, to its original sample or specimen. By making it possible to process amplification products from multiple samples or specimens in the same run, the team could make use of the machine’s great capacity.

The research team now wanted to test the idea. And it really did work! The results are now being published in the scientific web magazine PLoS ONE Publication.

According to Eske Willerslev, the new approach have great scientific potentials:

“Today, when using conventional methods to detect ancient DNA, we are only able to test a limited number of samples providing us with a somewhat random image of life in the past. Due to this new method, our knowledge will be put into a whole new perspective. For instance, finding out if species became endangered due to a dramatic change in the climate or if the decline in numbers started many years earlier than we originally thought or estimated”.

Contact:

Eske Willerslev, professor, Centre for Ancient Genetics, Phone: +45 3532-0570, Mob. +45 2875-1309 ewillerslev @ bi.ku.dk,

Jonas Binladen, PhD – student, Centre for Ancient Genetics, Mobile: +45 6067-2620, JBinladen @ bi.ku.dk

Woolly mammoth replica in a museum exhibit in Victoria, British Columbia, Canada. Foto: Encyclopædia Britannica

The climate is changing! But how does that affect nature? New research challenges traditional perceptions of contemporary climate as sole determiner of richness of species.

An international research team led by Professor Carsten Rahbek from Department of Biology, University of Copenhagen, questions traditional beliefs that contemporary climate alone determines richness of species, that is, how life is distributed on earth. The current issue of Science magazine highlights the research in Editor’s choice.

The research team argues that contemporary climate apparently only affects the geographical biodiversity of a few of the most widespread species – species that are rarely threatened by extinction. Evolutionary history, on the contrary, seems to play a major role for the dispersion of the majority of species – including rare and endangered species. Science magazine uses this research to emphasise once again that long-term strategies is necessary to preserve the earth’s biodiversity.

Professor Carsten Rahbek agrees and says: “The research mentioned in Science shows that climatic impact on the distribution of biodiversity is different from what we used to think. It is very likely that contemporary climate has an effect on individual species, but not in the way commonly believed”.

The result stems from analyses of almost 3,000 bird species (app. one third of the world’s species), conducted by the research team at the Danish Center for Macroecology, located at the Department of Biology. The research was mentioned in Science – not only because of its remarkable result – but because the results are based on a whole new ‘type’ of statistical models, which for the first time has made it possible to test the impact of climate on the distribution of life directly.

Contact: Professor Carsten Rahbek: phone: 3532 1030, e-mail: crahbek@bi.ku.dk

The ecliptic line is the projection of the plane of the earth’s orbit around the Sun onto the sky. It is an imaginary line in the sky that represents the plane of the earth’s orbit around the sun.

The equatorial line is the projection of the Earth’s equator onto the sky.

The earth’s orbital motion and the angle between the ecliptic plane and the equatorial plane cause the seasons.