Our new paper, published today open access in @PNASNews, uses neuroimaging genetics in up to 30,000 people from @uk_biobank, combined with ancient DNA sequences & comparative genomics, to investigate human brain evolution over a range of timescales. 1/9 pnas.org/doi/10.1073/pn… In this sequel to earlier @enigmabrains work, we failed to replicate signals of recent polygenic selection affecting surface area. The method used to detect selection can give spurious results due to population substructure; cohort here is more homogenous than in prior study. 2/9

In our new #GenLang preprint by Else Eising et al, we use genomics to investigate reading- & language-related skills in up to 34,000 people, directly assessed via psychometric testing. Years-long initiative uniting efforts of many dedicated colleagues: biorxiv.org/content/10.110… 1/n Our capacities for spoken & written language are central human traits but biological bases remain largely unknown. One way to gain insights is to identify genetic contributions to individual differences in relevant skills & use those as windows into neurobiology & evolution. 2/n

Twenty years ago today, our paper “A forkhead-domain gene is mutated in a severe speech & language disorder” was published: nature.com/articles/35097…. To mark the occasion, a personal thread about the journey we took to get to that point.
1/n Learning about human genetics as an undergrad, I found one emerging area of the field especially enticing. Scientists were discovering causes of major inherited disorders purely by analysing DNA of affected families, without needing prior knowledge of the biological pathways.
2/n

Remember when you first learned about genetics at school? All those fascinating examples of human traits that are each determined by just a single gene? Time to check in on some of your favourites to see how they’re doing...1/n Starting with a classic: the delicate art of tongue-rolling. Some people can roll sides of the tongue into a U-shape, others can’t. It’s commonly taught that this invaluable skill is controlled by one gene with dominant inheritance. But the idea was debunked decades ago...2/n

Collecting together my earlier Twitter threads exploring popular misconceptions about genetics. A thread of threads, beginning with a brief guide to heritability:

https://twitter.com/ProfSimonFisher/status/986923915481178113

Continuing a thread of threads on misconceptions about genetics, the case against "nature versus nurture":

https://twitter.com/ProfSimonFisher/status/1046786032325267456

Striking images can make scientific ideas accessible to people from all walks of life. But some such pictures do more damage than good, seeding confusion & fueling widespread misconceptions of an essential topic. Two iconic images & (mis)understanding evolution — a thread...1/10 First, an instantly recognizable image that, in our collective consciousness, has become inextricably tied to the very concept of evolution itself. Tragically for one of the most famous scientific illustrations ever, it is fundamentally flawed, & a potent driver of fallacy. 2/10

Links between genes & traits are complex & convoluted. But with the rise of genomic technologies perhaps it's no surprise that some people want to sell you lifestyle advice/products they claim are tailor-made for your DNA profile. Here's an example, h/t @AdamRutherford. 1/6 Let's talk "DNA personalized skincare", summed up by this screenshot from a website promoting it. (See: newstjohns.com/dna-personaliz…) The article mentions costs of $90-$200 for an at-home test kit & that on-site testing with some companies could set you back as much as $1,000. ...2/6

It was 20 years ago today that the US President & UK Prime Minister announced the completion of a rough draft of the human genome sequence. My family & friends didn't get why I (a geneticist myself) wasn't as excited for this landmark as they were. 1/4
nature.com/articles/d4158… Thing is, the publicly funded sequencing effort had been buzzing along well for some time, pieces of data released to the community as they were collected. Most gigging geneticists were already using available human genome data in our work. There was no sudden transformation. 2/4

With UFO sightings again making the headlines in these unsettling times, what we need right now is a thread on aliens, genes & the origins of human language. Buckle up. 1/n We discovered that rare mutations of FOXP2 cause a severe speech disorder. Over the years, I've spent much time stressing that FOXP2, while interesting, is not the mythical "gene for language". Weirdly, on occasion I've also had to explain why FOXP2 is not "proof of aliens". 2/n

What's it like to be a geneticist? A thread, based on stock photos sampled from the internet.
We begin with an image of a state-of-the-art genetics lab in action. Notice all the flasks & tubing filled with blue liquid, & the smart matching attire of these everyday researchers.1/n Expertise and precision in examining different coloured liquids is an essential skill in the day-to-day life of a geneticist. 2/n

Your genome is not a blueprint. A thread about misleading metaphors in science communication... 1/11 DNA is often referred to as a "blueprint for life". A blueprint is an architect plan, technical drawing or engineering design. Like a blueprint, DNA contains information to guide construction, in this case of a living organism. Beyond that, the analogy rapidly breaks down...2/11

Cool soundbites about genetics can confuse more than they clarify. An illustration. "You share 98.8% of your genes with a chimpanzee!" Is this true? What does it actually mean? Let's unpack this often quoted pearl of wisdom in a thread all about sharing...1/13 ...Statements about sharing genes are notoriously slippery. Here's another. "Identical twins share 100% of their genes, but non-identical twins share 50%, same as regular siblings." So, I share more genes with a chimpanzee (98.8%) than with my own sister? Something's up
...2/13

There's no such thing as a "gene for language". A Tweetorial to help explain why. In one branch of human genetics we search for correlations between particular gene variants that people carry and variations in an observed trait (normal variability and/or pathology)...1/9 "A gene for X" has become convenient shorthand to talk about associations between variation at these distant levels (genes & traits). This fuels a popular misconception of genes as abstract entities that can directly specify traits, including key aspects of human behaviour...2/9

Okay, it's time. Heritability in Five Easy Tweets:
Imagine studying a cohort of individuals (of the same species, let's say human) in a particular set of environmental circumstances. You assess everyone for some observable trait & find it varies from one person to the next...1/5 Heritability = an estimate of how much of the trait variability observed in your cohort may be accounted for by variability in genetic factors; a description of variance in that cohort under those conditions. Different cohorts/environments can yield different heritabilities...2/5