Question: Why do you want a frozen bat heart? Im interested!

Louise Johnson answered on 15 Jun 2010:

Thanks for asking! Here goes…

OK, Sian Harding will know a lot more about this than I do, because she has a whole lab working on the heart. But I found out recently from a friend who works on heart disease that our heart cells have different numbers of genes to our other cells, and I was really amazed.

You probably know that most of your cells have 2 copies of every gene – one from your mum and one from your dad. Heart cells copy all those genes again, sometimes more than once, so they have 4 or 8 or even more copies per cell. And we thought – why??

There are two reasons that other people have suggested for this. One is that maybe it’s just *better* to have more genes per cell. If that was true, then a heart that needed to work really hard – like a bat’s heart, because flying takes LOADS of energy – would have huge numbers of genes per cell.

The other is that it’s not great to have lots of genes per cell, but we have to do it because heart cells can’t beat and divide at the same time. Most parts of us grow by cell division, but not your heart – you have the same number of heart cells now as you did when you were 6 months old. They’re just bigger.
Now, bats are born relatively big for mammals, so their hearts don’t have very much growing to do. So if having lots of genes in the heart cells was just a way to cope with growing, bats’ hearts wouldn’t have lots of genes per cell.

So I thought looking at a bat’s heart might help us work out which of these explanations is the true one. I have another friend who studies bats, and she has lots of dead bats preserved in alcohol (she didn’t kill them just found them dead), but my heart scientist friend says that’s not good enough, she needs a frozen one or her gene counting techniques won’t work.

So there you have it!