This work came about as a bit of a surprise. We started out looking at whether we could see any differences in the genetics of wild frog populations that were infected with Ranavirus, compared to healthy populations.
When a disease outbreak happens, the main expectation is that you would see a loss of genetic diversity - the frogs that are susceptible to disease die and so the gene pool is reduced.
We didn't see any evidence of this in the frog populations infected with Ranavirus, despite the high numbers of deaths. We think that immigration might explain this - it only takes a few new frogs arriving in the pond to keep the genetic diversity up.
What we did see was a little more interesting... When we looked at individual animals from infected populations, we could see that each frog had parents that were genetically rather similar. But, when we looked at the infected population as a whole, the frogs were unexpectedly different to eachother. We didn't see this confusing pattern in uninfected populations.
What we think is happening is that in infected populations, healthy frogs mate with healthy frogs, and unhealthy frogs mate with unhealthy frogs. We think that healthy and unhealthy frogs differ genetically (see the last blog post). This would explain why the parents are genetically similar, but why the broader population looks quite diverse.
There could be a few explanations for this. Unhealthy frogs might just be unable to compete for a healthy mate, or healthy frogs might actively choose healthy mates. Either way, it looks like disease might be changing who mates with who. The implications are big - maybe this happens with lots of diseases? It could dramatically change how diseases are spread through populations.
The full paper is available here.
When a disease outbreak happens, the main expectation is that you would see a loss of genetic diversity - the frogs that are susceptible to disease die and so the gene pool is reduced.
We didn't see any evidence of this in the frog populations infected with Ranavirus, despite the high numbers of deaths. We think that immigration might explain this - it only takes a few new frogs arriving in the pond to keep the genetic diversity up.
What we did see was a little more interesting... When we looked at individual animals from infected populations, we could see that each frog had parents that were genetically rather similar. But, when we looked at the infected population as a whole, the frogs were unexpectedly different to eachother. We didn't see this confusing pattern in uninfected populations.
What we think is happening is that in infected populations, healthy frogs mate with healthy frogs, and unhealthy frogs mate with unhealthy frogs. We think that healthy and unhealthy frogs differ genetically (see the last blog post). This would explain why the parents are genetically similar, but why the broader population looks quite diverse.
There could be a few explanations for this. Unhealthy frogs might just be unable to compete for a healthy mate, or healthy frogs might actively choose healthy mates. Either way, it looks like disease might be changing who mates with who. The implications are big - maybe this happens with lots of diseases? It could dramatically change how diseases are spread through populations.
The full paper is available here.