Genetic sequences studied for koala retrovirus research
Researchers in the United States are working to collect the genetic sequences of koalas living in north America hoping it will help shed light on koala retrovirus. The virus can insert itself into a koala’s genome and has been associated with health issues such as immuno-suppression and cancer. The data will be combined with genetic information around the world including in Australia.
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TVTranscript
00:00 The koala is an iconic Australian animal, and it's Australian researchers who've been
00:07 studying it for longest.
00:09 Our museum was involved in 2018 with a foundational study that sequenced the genome of the animal
00:16 for the first time.
00:18 And all kinds of genetic work looking at the biology of koalas, their health, the threats
00:23 that they face, all of that kind of builds on that foundational block of having a genome
00:28 available.
00:29 And what do you do with that genome?
00:31 Actually, maybe what you should do is tell us a bit about this retrovirus and the effect
00:35 that it has and how having the sequence can help.
00:38 Sure, let me just take a minute and walk you through it because it's fantastic and really
00:41 interesting biology.
00:43 A retrovirus is a kind of virus that can come and infect a cell, and what it does is it
00:49 integrates itself into the DNA of a cell in your body.
00:52 And then it can transmit itself through, between individuals, making, I could get you sick
00:59 for example if I was spreading a retrovirus.
01:02 And depending on what kind of cell that it infects, it could cause all kinds of aspects
01:06 to go haywire in an animal.
01:09 It could cause cancers, et cetera, depending on where it's coming and infecting a cell.
01:14 The other aspect of it, and this is really interesting, is occasionally a retrovirus
01:18 might infect what we call a reproductive cell, like a sperm or an egg cell.
01:22 In that case, it can actually become a permanent part of an animal's DNA because the mother
01:28 or father will pass it down generation after generation.
01:32 And a lot of the DNA that we have in our own cells, we know this from sequencing the human
01:38 genome and others, is that maybe 10%, 5% or 10% of our own DNA comes from those kinds
01:44 of viral infections.
01:46 Koalas have a very special one.
01:48 They have a retroviral infection that is in the process now of integrating itself into
01:54 the genome, but they also have free living infections from retrovirus.
01:58 This affects their health, it makes them susceptible to cancer, it taxes their immune system, and
02:03 can make them susceptible to all kinds of diseases.
02:06 And we know that koalas are an endangered species, so I guess with a limited pool of
02:11 DNA, the risk is that that becomes entrenched.
02:14 That's right.
02:15 Koalas are in decline across New South Wales, Queensland.
02:18 It's really important that we understand their health better towards effective conservation.
02:25 So this work now that's happening in the US, bring that in, does that mean what we're essentially
02:29 building up here and researchers are going to have their hands on is the biggest collection
02:33 of koala DNA in recorded history?
02:37 Well, you might ask, why is this work happening in North America?
02:40 I will ask you that.
02:43 And it's actually a serendipitous thing, a really lucky thing in a way.
02:47 Koalas were sent to the San Diego Zoo in the 1970s and they've been there ever since.
02:52 And so there's been a limited gene pool there that they've been breeding them from.
02:56 And one thing they've been doing is collecting their tissue, their DNA, and putting it in
03:02 the freezer since the 1970s.
03:04 So they know how they're all related and how they've been bred, so they can map out family
03:08 trees, go back for decades, look at their death records, see which ones may have died
03:15 from cancer or other things, sadly, and then come and map that back to understanding with
03:20 new genetic techniques, new sequencing techniques for DNA, bringing out these old samples and
03:26 looking at patterns and how the retrovirus might have inserted itself, might have caused
03:31 disease.
03:33 We're hoping this is a clue, a way to kind of unlock patterns in how this virus affects
03:38 the health of koalas so we can better understand how to look after them.
03:42 Chris, I reckon we could talk about this for hours, but we don't have that much time.
03:45 So I'll just ask you one more question, and that is, what practically will this mean for
03:50 koala conservation?
03:51 How can you use this then in terms of in the short term or in the short to medium term?
03:57 Two things.
03:58 One is people are really excited to understand this better because it has human health implications.
04:03 But I think most of us, especially in Australia, would be excited if this can just have positive
04:09 benefits for the health of koalas themselves.
04:12 This is one of the best ways into understanding how does a virus like this cause disease like
04:18 cancer or make koalas susceptible to other diseases like chlamydia that are so, so devastating
04:25 for our nation's koala populations.
04:27 [BLANK_AUDIO]