Targeting Alzheimers, Sequencing the Iceman, Sex Selection in hippos and Giant Penguins

04 March 2012

Interview with 

Li-Huei Tsai, MIT; Albert Zink, European Academy of Bolzana; Joseph Saragusty, Leibniz Institute for Zoo and Wildlife Research; Dan Ksepka, North Carolina State University explains


kairuku penguin


Protecting the memory of Alzheimer's patients

new drug targethas been identified to fight the memory loss and dementia seen in Alzheimer's patients.

Using mouse models, Li-Huei Tsai, from the Massachusetts Institute of Technology, identified increased levels of the enzyme Histone Deacetylase 2, or HDAC2, in mice with the disease. 

The enzyme is known to play a role regulating the expression of genes involved with memory but it's increase can result in a blockade of these genes resulting in impaired memory formation and a decline in cognitive function.

Li-Huei -   I think the good news from our study is that this blockade of impulses by the elevation of HDAC2 enzyme is potentially reversible.  So, we are very hopeful that by coming up with inhibitors of HDAC2, that it will one day be possible clinically to recover cognitive function in Alzheimer's patients in terms of learning a memory.


Otzi the Iceman's Genome

Otzi memorialThe
genome of Ötzi, the 5300 year old iceman, has been sequenced by scientists at the European Academy of Bolzana.

Previous studies have shown that Otzi, was over a metre and a half in height, lived in the Southern Alps and was killed at the age of 46 by an arrow. But now, his genome has revealed detailed characteristics of his physiology such as brown eyes, lactose intolerance and his blood group being O as well as a predisposition to certain diseases providing insight into not only his health, but also our evolution as Albert Zink explains...

Albert -   So we found that he suffered from Lime disease and this is the oldest evidence for this disease that we have so far.  He also has a genetic predisposition for coronary heart diseases.  It was not known that this kind of diseases are that old.  We know now better about his ancestry, that he belonged to a population that came to Europe in the Neolithics and nowadays, we have this kind of population still present in Sardinia and Corsica where we found the same genetic structure but in the rest of Europe, this signature is mainly replaced.


Favouring Females in Hippo populations

Male pygmy hippos change the composition of their sperm to reduce the number of males born into the next generation.

Working with endangered pygmy hippos in a captive environment,  Joseph Saragusty from the Leibniz Institute for Zoo and Wildlife Research found that male members of the group produced sperm with higher levels of X chromosomes than Y chromosomes, meaning more females, of genotype XX, rather than males, of genotype XY, will be born into the next generation.

This results in less competition between the territorial males but could also be exploited to improve conservation methods.

Joseph -   In many endangered species, it would be better if we could have a little bit more females than males because females are the ones that produce the offspring.  Then we have a better chance to save populations from extinction.  The next stage would be to find the mechanism how they do it and once we have this in hand, we might be able to influence this mechanism or activate it when we want to.


Reconstructing a Giant Penguin

And finally, a large, extinct penguin which lived 25 million years ago has been kairuku penguinreconstructed using fossil remains in New Zealand.

The kairuku penguin, named after a Maori word for 'diver who returns with food', was pieced together using two incomplete skeletons of the bird revealing a penguin with a slender body plan, standing at 4ft 2 in height with an elongated beak and long flippers.

The penguin provides new insight into the ecosystem of New Zealand at this time period, as Dan Ksepka from North Carolina State University explains.

Dan -   It turns out there's 5 different penguin species of all different sizes living side by side at about 27 million years ago.  So this is part of a fauna of penguins.  They're a very, very important component of that ecosystem and based on their evolutionary relationships, we see that these penguins are actually a side experiment.  They are a branch of the penguin tree that separated from the main trunk, evolved for several million years and they were very successful during that time. But ultimately, they died out and did not leave any living descendants but during that time, very, very important to the ecosystem.

The work was published this week in the journal Vertebrate Paleontology.


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