Lab-grown mini brains shed light on how humans split from great apes – The Conversation UK
By daniellenierenberg
Humans diverged from chimpanzees and other great apes roughly 6m years ago. But despite us being closely related, human brains are vastly different enabling us to engage in complex language, science, art, morality and much more. But what exactly was it that enabled our brains to reach such mindboggling heights?
We know that the human brain has dramatically expanded in size over the past 6m years. Humans are in fact the mammals with the largest brain relative to body size. But which specific evolutionary genetic changes enabled larger and more complex brains has long remained a bit of a mystery. Now a new study, published in Nature, offers clues.
One important reason why it has been so hard to study primate brain development is that, until relatively recently, scientists did not have access to living, developing brain tissue. This is what can ultimately allow us to functionally test theories of brain evolution as we can essentially watch how a brain develops over time in a dish and manipulate biological pathways to see what role they play in brain development.
But in the last few years, scientists have worked out how to make lab-grown models of developing brain tissue so-called brain organoids to begin to address these questions.
Organoids are clusters of cells that organise themselves into mini versions of our organs, such as the brain or the liver. Thats because they are made by culturing stem cells, which have the potential to develop into any tissue of the body. These stem cells can be generated directly from cells of adult origin, such as skin or blood cells. They are then grown in a gel that allows them to develop three dimensionally. And thats exactly what the researchers behind the new study did.
So what kind of genetic changes do we think contributed to human brain evolution? Only about 1.5% of our DNA actually consists of genes with instructions for making proteins. Proteins are the molecules that do most of the work in cells and determine the cells structure and function. It was once thought that the remaining 98.5% of DNA was junk with no clear purpose. However, it is now known that some of this DNA may play an important role in controlling which genes are expressed meaning determining how they are turned on and off.
The number of changes in protein-coding regions of DNA are far too few to explain the striking differences observed between humans and other primates. In fact, of the genetic regions that have changed the most since our divergence from chimpanzees, 92% do not overlap with protein-coding DNA.
It is predicted that at least a third of these regions play a role in controlling the expression of genes. It has long been hypothesised that the majority of differences observed between the brains of great apes and us are due to changes in the timing and expression of genes, rather than changes to the gene itself. The vast majority of our genes are therefore identical.
The main focus of the new study was to identify how genes are regulated differently in humans compared to other primates. The authors did this by generating brain organoids from human, chimpanzee and macaque stem cells and compared these at various points over the course of four months. This mimics how a brain forms in the womb, with organoids consisting of multiple growing buds of brain tissue that first consist largely of neural progenitor cells that in later stages begin to make neurons.
From the outside, brain organoids look more like small popcorn than a mini brain and do not reach sizes larger than around five or six millimetres due to a lack of blood supply.
The authors observed that human brain development occurs at a slower pace than the other two primates. This delayed maturation of the human brain makes sense as, given more time, the cells that generate neurons will have a longer period to expand their population, giving rise to more neurons and a bigger brain later on.
The researchers were also able to look at the expression of genes in individual cell types of the brain organoids. They measured the expression of a gene by looking at the levels of a messenger molecule that is made from reading DNA and is necessary to direct the formation of proteins. By comparing gene expression in cells that were developing to become the cerebral cortex which plays an important role in advanced cognitive processes such as awareness, thought, memory, language and consciousness they detected 98 genes that were differently expressed in humans.
Gene expression doesnt tell the whole story though. Its rate is ultimately controlled by a process called gene regulation. In order to identify potential regulatory mechanisms, the authors pinpointed regions of DNA that are accessible or open at the various stages in particular cells. These accessible regions of DNA have the potential to interact with proteins and can regulate gene expression.
By comparing organoids between human and chimpanzee, the researchers were able to identify regions of DNA that were differently accessible in humans potentially playing a regulatory role. Regulatory regions of DNA are more likely to be found in close proximity to the genes they are regulating the expression of. More than 60% of the genes that were expressed differently in humans were also in close proximity to differently accessible regions. This suggests that human-specific development and gene expression is a result of evolutionary changes in regions of DNA that are capable of regulating gene expression.
A significant proportion of the regions of DNA that we already know have changed the most since our divergence from chimps were found to overlap with those being different in terms of accessibility suggesting the team has indeed highlighted key regulatory processes responsible for making us humans.
This study takes the first steps in pinpointing interesting candidate genetic regions responsible for human brain complexity. The authors do not dive deeper into the mechanisms of what the altered expression of a specific gene actually means in terms of how the brain grows and functions. It does, however, provide an excellent resource and starting point to direct future research in this direction.
This research is not only important in understanding what makes us human, but also in working out how certain human disorders may arise. Several studies have found that mutations in regions of DNA with human-specific changes are associated with neurodevelopmental disorders.
Read the original:
Lab-grown mini brains shed light on how humans split from great apes - The Conversation UK
- Colossal Creates Elephant Stem Cells for the First Time in Quest to Revive the Woolly Mammoth - Singularity Hub - March 18th, 2024
- Vitamin A could have a key role in both stem cell biology and wound healing: Study - Medical Dialogues - March 10th, 2024
- A dive into the genetic history of India, and the role of vitamin A in skin repair - Science - March 10th, 2024
- Herbosa: Clinic under probe after skin treatments linked to womans death - Philstar.com - January 22nd, 2024
- These Will Be the Biggest Skin-Care Trends of 2024 - Allure - December 28th, 2023
- Sorry, But These 10 Skincare Products Are A Scam - Refinery29 - December 12th, 2023
- Cyclerion Strengthens Board of Directors with Experienced Company Builder and Cutting-edge Innovator - December 4th, 2023
- Aptose Appoints Fletcher Payne Chief Business Officer, Expanding his Executive Role - December 4th, 2023
- Opthea to Present at the FLORetina 2023 Congress - December 4th, 2023
- HUTCHMED Highlights Clinical Data to be Presented at 2023 ESMO Asia and ESMO Immuno-Oncology Congresses - December 4th, 2023
- AC Immune Strengthens Management, Appoints Madiha Derouazi as CSO and Christopher Roberts as CFO - December 4th, 2023
- Publication of a transparency notification received from Tolefi SA (Article 14 §1 of the Law of 2 May 2007) - December 4th, 2023
- Annovis Bio Appoints Andrew Walsh as Vice President Finance - December 4th, 2023
- Foghorn Therapeutics Announces Clinical Data from Phase 1 Study of FHD-286, a Novel BRG1/BRM Inhibitor, in Patients with Advanced Hematologic... - December 4th, 2023
- Akari Therapeutics Appoints Experienced Life Sciences Entrepreneur Samir R. Patel, M.D. to Board of Directors - December 4th, 2023
- Ovid Therapeutics to Present Five Abstracts Supporting its Epilepsy Programs at the 77th American Epilepsy Society Annual Meeting (2023) - December 4th, 2023
- Spectral Medical Announces CFO Departure - December 4th, 2023
- Are STEM CELL EXOSOMES the secret to a 'snatched' jawline? Discover the products that influencers are claiming - Daily Mail - November 18th, 2023
- Defence Mechanisms: Four ways your body is protecting you every time you fall sick - indulgexpress - May 16th, 2023
- Treat Yourself to a Spa Day With a $100 Deal on $600 Worth of Products From Elemis, 111SKIN, Nest & More - E! NEWS - May 16th, 2023
- INTERNATIONAL STEM CELL CORP MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS (form 10-K) - Marketscreener.com - April 5th, 2023
- Skin Regeneration: The Science and How to Boost It - Healthline - March 9th, 2023
- Treat Yourself to a Spa Day With a $100 Deal on $600 Worth of Products From Elemis, U Beauty, Nest & More - E! NEWS - March 1st, 2023
- 7-year-old vows to find a cure for brother in need of bone marrow transplant - WJLA - February 21st, 2023
- World's most radioactive man 'cried blood' as his skin melted in 83-day nightmare - Times Now - February 4th, 2023
- How old are you, really? The answer is written on your face. - National Geographic UK - February 4th, 2023
- Skin: Layers, Structure and Function - Cleveland Clinic - January 27th, 2023
- Human skin | Definition, Layers, Types, & Facts | Britannica - January 27th, 2023
- Skin Disorders: Pictures, Causes, Symptoms, and Treatment - Healthline - January 27th, 2023
- Skin care: 5 tips for healthy skin - Mayo Clinic - January 27th, 2023
- Skin Care and Aging | National Institute on Aging - January 27th, 2023
- Wrinkles - Symptoms and causes - Mayo Clinic - January 27th, 2023
- Dry skin - Symptoms and causes - Mayo Clinic - January 27th, 2023
- Stem cells: a brief history and outlook - Science in the News - January 3rd, 2023
- Still Drinking Green Tea? Doctor Reveals A Healthier Drink With Proven Benefits For Diabetes, Aging, Oxidative Stress, And Cancer - Revyuh - January 3rd, 2023
- RUDN Physician And Russian Scientists Investigate Long-term Effects Of Treating Diabetic Ulcers With Stem Cells - India Education Diary - December 25th, 2022
- The Use of Stem Cells in Burn Wound Healing: A Review - Hindawi - December 1st, 2022
- FACTORFIVE Skincare The Power of Stem Cells for Skin - December 1st, 2022
- Embryonic Stem Cells - The Definitive Guide | Biology Dictionary - December 1st, 2022
- From pro soccer hopeful to hip hop artist with illness and addiction along the way, Tymaz Bagbani releases debut album - Toronto Star - December 1st, 2022
- Stem Cells | The ALS Association - November 22nd, 2022
- What is a stem cell? YourGenome - October 29th, 2022
- Skin Cell - The Definitive Guide | Biology Dictionary - October 29th, 2022
- Explora Journeys Plans Extensive Fitness And Well-Being Initiatives At Sea, Right On Trend - Forbes - October 29th, 2022
- Ahead of the holiday shopping season, Amazon kicks off second annual Holiday Beauty Haul on Oct. 24 - KXAN.com - October 21st, 2022
- Human skin color - Wikipedia - October 13th, 2022
- Mesenchymal Stem Cells | Properties, Process, Functions, & Therapies - October 13th, 2022
- Skin Grafting, Cryopreservation, and Diseases: A Review Article - Cureus - October 13th, 2022
- Anti-ageing cosmetics: Can they turn back the hands of the clock? - The Sunday Guardian Live - The Sunday Guardian - October 13th, 2022
- Brennand named Elizabeth Mears and House Jameson Professor of Psychiatry - Yale News - October 13th, 2022
- The Switch to Regenerative Medicine - Dermatology Times - October 13th, 2022
- Last Chance to Get The Collagen-Infused Massage Oil That Moisturizes Skin & Diminishes Cellulite For Less Than $20 - msnNOW - October 13th, 2022
- Addison's Disease Explained: Causes, Symptoms, And Treatments - Health Digest - October 13th, 2022
- Stem Cells Therapy for Autism: Does it Work? - October 5th, 2022
- Stem-like CD8 T cells mediate response of adoptive cell ... - PubMed - October 5th, 2022
- 6 Under Eye Products You Need To Have STAT - Grazia India - October 5th, 2022
- CellResearch Corporation (CRC) to present promising new stem cell products for the treatment of chronic diabetic foot ulcers at the world's premier... - September 27th, 2022
- Reprogramming pig cells leads way for new regenerative therapies - National Hog Farmer - September 27th, 2022
- A glimpse into Indian consumers expectations for cosmetic treatments and consumption insights - The Financial Express - September 27th, 2022
- Tajmeel redefines beauty to give its patients the best results - Gulf News - September 27th, 2022
- Here Is Why You Heal Slower As You Age - Health Digest - September 27th, 2022
- Creating stem cells from minipigs offers promise for improved treatments - University of Wisconsin-Madison - September 19th, 2022
- Israeli Biotech Firm Plans to Create Human Embryos to Harvest Organs, Field Experts Say There are Ethical Concerns - CBN.com - September 19th, 2022
- CellResearch Corporation (CRC) announces positive results of Phase I study for CorLiCyte - PR Newswire - September 19th, 2022
- The best CBD and hemp products for pampering your skin this fall - Leafly - September 19th, 2022
- Benjamin Button For Real? Scientists Are Close To Cracking The Code To Reverse Aging - Worldcrunch - September 19th, 2022
- I took an international trip with my frozen eggs to learn about the fertility industry - MIT Technology Review - September 19th, 2022
- Propanc Biopharma Reports Significant Effects of PRP Against the Tumor Microenvironment - Business Wire - September 11th, 2022
- 6 Ingredients to Avoid Putting on Your Skin - Healthline - September 3rd, 2022
- Regenerative Properties of the Newborn Heart Offers Hope for Those With Congenital Heart Disease - The Epoch Times - September 3rd, 2022
- Meet White Orange: The Vitamin C Skin Care Brand For Sensitive Skin - Bustle - September 3rd, 2022
- Rejuvenation Roundup August 2022 - Lifespan.io News - September 3rd, 2022
- To better understand Parkinson's disease, this San Diego expert sent her own cells to space - The San Diego Union-Tribune - August 26th, 2022
- Inside the race to make human sex cells in the lab - MIT Technology Review - August 26th, 2022
- Global Biomaterials Market to Reach Value of $372.7 Billion by 2028 | Demand For Biomaterials in the Healthcare Industry will Grow by 53% Over the... - August 26th, 2022
- A Groovy Guide to Anti-Aging Products With CBD and Mushrooms - Out Magazine - August 26th, 2022
- New milestone organoid synthesis will boost disease and drug development research - RegMedNet - August 10th, 2022
- Victoria Beckham and Kim Kardashian are fans of Augustinus Baders skincare range - and you can get 20% off - The Mirror - August 10th, 2022
- Mutant T Cells That Drive Amyotrophic Lateral Sclerosis (ALS) Progression May React To a Brain Antigen - The Scientist - August 10th, 2022
- Why Glucose Restrictions Are Essential in Treating Cancer - The Epoch Times - August 10th, 2022