#266 - AMA #50: Genetics: how they impact disease risk, what you can do about it, testing, and more
In this AMA, Dr. Peter Attia explores the fundamentals of genetics and its relation to disease. He discusses reasons for genetic testing, its utility, types, and how to interpret results, especially for commercial direct-to-consumer tests.
Deep Dive Analysis
7 Topic Outline
Introduction to AMA #50: Focus on Genetics
Defining Genetics and its Importance
Understanding DNA, its Function, and Gene Expression
How Genetics are Passed Down: From Base Pairs to Chromosomes
Genetic Variation: SNPs and Human Genetic Identity
Heritability of Traits: Nature vs. Nurture
The Value of Twin Studies in Genetics Research
6 Key Concepts
Genetics
Genetics refers to the 'nature' part of a person, encompassing traits passed down from parents. It plays a crucial role in understanding physical, psychological, and social factors, and while genes themselves cannot be changed (barring engineering), understanding them can inform lifestyle modifications to manage risk for various conditions.
DNA
DNA is a code of instructions that dictates how a cell functions, analogous to a cookbook with individual recipes. It consists of a string of nucleotides (G, C, A, T) that pair together, forming a double helix structure. These lengthy strings are divided into segments known as genes.
Gene Expression
Gene expression is the process by which genes become functional. It involves transcribing a copy of DNA into RNA, and then translating that RNA into a protein. Proteins are essential for carrying out nearly all cellular functions, acting as enzymes, cofactors, and structural components.
Alleles
Alleles are different versions of a gene. Humans receive two copies of every gene, one from each parent, and these copies can be identical or different. Some traits result from the combined effect of both alleles, while others follow a dominance pattern where one allele's trait is expressed over the other.
SNPs (Single Nucleotide Polymorphisms)
SNPs are small variations in the sequence of genes or surrounding DNA that occur across individuals. Despite humans being over 99.5% genetically identical, these tiny variations, present in less than 0.5% of the genome, account for all genetically attributable differences in human traits like height, hair color, and disease susceptibility.
Heritability
Heritability describes the extent to which a trait or health characteristic in a population is determined by genetics. It quantifies the amount of phenotypic variation attributable to genetic variation, with most traits being influenced by a combination of genetics, environment, and experience.
5 Questions Answered
Genetics refers to the inherited 'nature' component of a person, passed down from parents. It's important for understanding how genes shape and predispose individuals to various conditions, potentially guiding lifestyle modifications to manage health risks.
DNA is the code of instructions that tells a cell how to function, organized into genes. It impacts biology by being expressed (transcribed into RNA and translated into proteins), which then carry out virtually all necessary functions within a cell.
Genetics are passed down through DNA, which is organized into 23 pairs of chromosomes. Each pair consists of one chromosome from the mother and one from the father, meaning individuals receive two copies (alleles) of every gene.
Despite individual distinctiveness, all humans are at least 99.5% genetically identical. The small variations, called SNPs (single nucleotide polymorphisms), present in less than 0.5% of the genome, account for all genetically attributable differences in human traits and disease susceptibility.
Some traits like blood type and eye color are 100% heritable (genetically determined), while others like native language and religion are 0% heritable (environmentally determined). Most traits, such as height (80% heritable) or susceptibility to conditions like schizophrenia (79-80% heritable), result from a complex interaction between genetics, environment, and experience.
2 Actionable Insights
1. Become a Savvy Genetic Consumer
Educate yourself on the basics of genetics, the reasons for testing, available test types, and result interpretation. This foundation helps you critically evaluate and utilize commercial direct-to-consumer genetic tests effectively.
2. Influence Traits with Environment
Recognize that many traits are shaped by a combination of genetics and environmental factors. For example, optimize childhood and gestational nutrition and avoid hazardous exposures to positively influence non-genetic components of traits like height.
3 Key Quotes
I tend to think that people overweight the importance of genetic testing. I've certainly been vocal about that, but I want to call out areas where I think genetic testing can be valuable.
Peter Attia
Humans only have about 20,000 protein coding genes in total. Maybe that sounds like a lot, but if you consider the fact that lab mice on average have about 23, 25,000 genes, krill these tiny sea plants, whatever, we're talking about like 29,000 genes, rice, mushrooms, maybe 50,000 genes. So when you think about things that are far simpler than we are and they have far more protein coding genes, you realize that that's just part of the story.
Peter Attia
We are still 99.5 percent or greater genetically identical in fact all humans are at least 99.5 percent genetically identical to each other again pretty remarkable that snips are only present in less than 0.5 percent of all base pairs for the entire human genome and yet that small small variation accounts for all the genetically attributable differences in variability across humans in height hair skin color susceptibility to diseases everything like you name it all the things about us that are genetically different are contained within less than 0.5 percent of our genome.
Peter Attia