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]
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