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Good morning all, As our term comes to a close, I'll use my last news message to send along the latest news from two ongoing news stories in genetics: The first bit of news is about a newly reported fossil find, from a branch of ancestral hominins known as the Denisovans. While scientists and anthropologists have been studying our Neanderthal relatives for decades, Denisovans are only recently discovered. They are thought to have represented a 3rd lineage of ancestral hominin, that co-existed with and likely inter-bred with both Neanderthals as well as early humans. Until very recently, all information on Denisovans came from fossils collected from a single location, the Denisova cave in modern Siberia (Russia). This new report describes a Denisova fossil from much farther south, in modern Tibet, which suggests that Denisovans were more broadly distributed, expanding the ranges of times and locations over which they may have interacted with modern humans. We know so little about Denisovans that this new information has been described as 'game changing'. If you recall the patterns of early human migration we considered, the first humans may well have had opportunity to interact with the last Denisovans. We all likely have some 'Neanderthal DNA' in us; we may come to realize that we all have a little 'Denisovan DNA', too. https://www.nytimes.com/2019/05/01/science/denisovans-tibet-jawbone-dna.html The second news story I will send here relates to the promise, and difficulty, of genome editing. We've discussed a number of times the concept of genes and alleles, and we've considered both gene therapy as well as some of the news related to human genome editing. Recently, a group of prominent scientists has argued that, given our current state of knowledge, the use of gene editing to produce 'designer babies' is more fiction than fact. Even apart from the difficulty of successfully edited the human genome, they suggest that the likelihood of finding individual genes with pronounced effects is very, very low. If you remember, genome-wide association studies (GWAS) can be used to identify genes associated with particular aspects of our physiology and health, but the strength of these associations normally is very low (e.g., often <1%). As such, we may not yet have good, individual targets for gene manipulation. https://www.npr.org/sections/health-shots/2019/05/02/719665841/why-making-a-designer-baby-would-be-easier-said-than-done That said, it is very likely that both our gene-editing as well as our genome evaluation skills are going to improve over time, so perhaps the current limitations on the likelihood of 'designer genome editing' are just that: current, but not permanent. It seems impossible that this topic, or interest in it, is going away any time soon. I'm signing off for the term now. I hope that these weekly news messages have been useful to you. This is the first semester that I have used them to this extent, and it has been a learning experience for me. In particular,
In the end, though, I remain very optimistic. Science is "mankind's organized quest for knowledge" (Floyd Bloom), and we already know that "knowledge is power" (Francis Bacon). It is science that offers us the best hope to deeper understanding, new therapies and treatments, new cures, and new adventures. We will encounter many speed-bumps along the way, to be sure. I hope that our course has inspired you to be a part of this quest, and to make the best use of the knowledge that you gain while on it. Have a great weekend, and best of luck with all of your exams next week. Dr. Nealen
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