Genetics of Bats for Dummies

Greater mouse- eared bat at Ratkova

 

Emma is a warm, friendly person with a total mastery of her subject and with the gift that very few people possess - that of transmitting complicated information in a form that makes it understandable to the average Joe in the street.

It was full of terms such as telomeres, mitochondria, blood transcriptome, laryngeal echolocators but ….it was aided by great visual aids and her explanations were crystal clear.

Bats live for an inordinate length of time. Usually long-lived animals are very large, viz,  blue whales, elephants etc, and smaller animals have short life spans. But bats buck this trend in a major fashion. Brandt’s bats (Myotis brandtii) have been recently recorded as living for 43 years. For an animal that weighs 7gms on average. And that individual showed no sign that it was ancient. Bats live, on average, for ten times the norm expected for their size and when all the animals of the world are plotted on a graph according to their longevity and their size, 17 out of the 18 of the anomalies to the rule that bigger animals live longer, are bats, and the other is the naked mole rat.

Bats have a lifestyle that is very demanding since flight requires a lot more energy than terrestrial locomotion, so they should die young. House mice weigh about 3 times as much as Brandt’s bats and they are terrestrial, but they only live for up to two years.

It is common knowledge that the lifespan of humans has increased over recent generations but after the age of 60 or so many people suffer from the effects of ageing and they may live longer but they often don’t live healthily. Bats, however, not only live for a long time but they are extremely resistant to diseases, including all forms of cancer, and to the ravages of inflammation, which my arthritic fingers feel more and more.

So, Emma Teeling set out to try and find out if their molecular structure could reveal the secret to their longevity and to their disease resistance, and if this could help humans live not only longer, but without endless hospital visits. Most researchers on these topics use animals which, as Emma says, “are good at dying, but not good at living”. Examples would be drosophila fruit flies and mice. Bats are the antithesis of this.

She and her colleagues at UCD have conducted most of their field work in Brittany on populations of greater mouse-eared bats (Myotis myotis) that mostly breed in lovely old churches. It wasn’t easy. They have had, especially in the early years, moments when “they sat in the middle of a field at 3 o’clock in the morning and cried!”  Olivier Farcy and his dedicated band of volunteers helped enormously with this work, which is now entering its 11th year.

To conduct the study, researchers took a few drops of blood from more than 100 wild bats, and also took tiny wing-punches of tissue. The individuals are marked with microchips.

To uncover how this “anti-ageing” gene expression pattern is controlled in bats, they sequenced small regulatory genes knows as “microRNAs” and uncovered key genes that may control “the longevity pathway” in the species. Blood samples were flash frozen in liquid nitrogen, and high-quality RNA, in effect “the message from expressed genes”, was extracted, sequenced and compared across different aged individuals. Previously, the team showed that in long-lived bats “telomeres”, the protective ends on their chromosomes, did not shorten with age. This is usually a consequence of getting older, and this new study indicates the genes driving this. The team also examined the way that bats’ cells aren’t damaged by ‘free radicals’, that is the oxygenation process where unstable atoms are linked to ageing and to a host of diseases, including cancers. Bat flight is a highly energetic process during which large quantities of free radicals are produced, but surprisingly no evidence of damage by these was found in bats of all ages. Bats also increase the maintenance of DNA as they age, so that in summary they do four separate things. They repair DNA, they remove damaged cells, they maintain telomeres and they balance immunity.  All this has implications for unlocking the secrets to help humans age healthily.

The study works in conjunction with bat1K, which is an initiative to sequence the genomes of all living bat species (1400 species). Emma is very keen that as many people as possible sign up to this. More details can be found on the web site  https://bat1k.com/.

To this end all bat workers can help by sending the bodies of freshly dead bats to her at UCD. If people wish to know details of how to do this, please contact Charlie at membership@batgroup.org.uk

Emma also quoted from a paper printed in the journal Nature last year. At present, there is no direct evidence to link the outbreak of COVID19 to bats. This paper can be found here:

https://www.nature.com/articles/s41564-020-0771-4

The greatest diversity of coronavirus is found in bats, and investigations have been carried out into bats in Wuhan, in Hubei province in China, where the present epidemic originated. Up to now, species of horseshoe bats (Rhinolophidae) have been found with viruses with up to 99% of the RNA identical to COVID 19 but not one species has been found that is 100% identical.

Listening to Emma, I was struck by two main thoughts. The first was we have always known that these animals are really special and astounding, but their fantastic abilities in the realm of combating ageing and disease are only now being understood.

My second thought that it is such a shame that we often view our relationship with animals through an anthropocentric prism. In other words, we only evaluate them through the use that they can be to us, or in their relationships with us. Although the fact bats might enable mankind to age more healthily did perhaps open the door to Emma to get funding?

Thank you so much Professor Emma Teeling!            

 

By Charlie Liggett