DNA

Runaway inbreeding: how runs of homozygosity impact conservation management

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On the precipice

Species which exist in fragmented, isolated and reduced populations have elevated extinction risk. Not only are they more susceptible to demographic and environmental stochasticity, which can easily wipe out small populations, but they also suffer from a range of genetic impacts. Notably, populations often lose significant amounts of genetic diversity as they reduce in size, potentially losing important adaptive diversity enabling them to respond to current and future environmental change. At the same time, random genetic drift becomes stronger relative to natural selection, reducing the efficacy of selection to be able to increase the frequency of favourable alleles and reduce the frequency of maladaptive ones. Together, these impacts create feedback loops which hasten the decline into the extinction vortex.

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Building Blueprints – How to assemble a genome

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The utility of a reference genome

In the 18 years since the completion of the Human Genome Project, the practicality of assembling full genomes for a wide range of taxa beyond ourselves has only improved. While model taxa systems have achieved genomes before many others, it is now possible for whole genomes to be assembled for a range of non-model organisms as well. But how do we assemble the genome of a species for the very first time (often de novo – literally “from the new”)? What can we do with this genome? Why is it so useful? Let’s delve into the process and outcomes of genome assembly a little more.

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Sweeping under the genomic rug: hard and soft sweeps

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Of alleles and selection

If you’ve read this blog more than once before, you’re probably sick of hearing about how genetic variation underlies adaptation. It’s probably the most central theme of this blog, and similarly one of the biggest components of contemporary biology. We’ve talked about different types of selection; different types of genes; different ways genes and selection can interact. And believe it or not, there’s still heaps to talk about! Continue reading →

Managing genes in conservation and industry

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The fundamentals of population genetics

Many times in the past, we’ve discussed the importance of genetic diversity within populations as a foundation for adaptation and evolution. It includes both adaptive variation (which encompasses genetic variation directly under natural selection), as well as neutral variation (which is predominantly generated and maintained by non-selective forces such as demographic history and genetic drift). This pool of genetic variation acts as the underlying architecture for evolution by natural selection, and is a critically important component for future and ongoing evolution.

This all sounds important from an academic perspective: that population genetics can reveal a significant amount of information about the processes and outcomes of evolution and provide novel insights into concepts that have been around for ages. But how can this information be applied to real scenarios? With the ever-growing availability of massive genetic datasets for an increasing number of species, the sheer volume of information in existence that can be used is monumental.

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Rebuilding the genomic architecture of evolution

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Beyond mutations in the genome

Although genetic variation is, in itself, often considered to be one of the fundamental underpinnings of adaptation by natural selection, it can appear through a number of different forms. Typically, we think of genetic variation in terms of individual mutations at a single site (referred to as ‘single nucleotide polymorphisms’, or SNPs), which may vary in frequency across a population or species in response to selective pressures. However, we’ve also discussed some other types of genetic-related variation within The G-CAT before, such as differential gene expression or epigenetic markers.

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