6 A Framework for Thinking About Race Differences
Part II discusses how to think about differences between races. It starts by explaining that, while people accept major genetic differences related to sex, many believe that significant genetic differences in cognitive abilities across races are impossible. The goal is to show that it makes sense to expect some cognitive differences among races could be partly genetic. This idea is based on research done over the last 30 years. Important points include that human groups have unique genetic traits linked to their race, that evolution has changed populations since humans left Africa, and that genetic differences related to cognitive abilities among races are common. Each point will be explored further in the following chapters.
What the Orthodoxy Gets Right
The discussion points out that some ideas about race from history were wrong and that differences between races only make up a small part of human diversity. It agrees that while race is not completely meaningless, we should move away from the term "race" because it has a lot of negative history linked to racism and colonialism. Instead, it suggests using terms like "ancestral population" to more accurately describe genetic differences and our shared human history.
Third Interlude: Genetic Terms You Need to Know to Read the Rest of the Book
Genetic terminology is essential for understanding key concepts in genetics. A genome is made up of two strands of DNA arranged in a double helix found in the nucleus of cells. In humans, each DNA strand contains over three billion base pairs made from four chemicals: adenine (A), thymine (T), guanine (G), and cytosine (C). Base pairs are linked by hydrogen bonds, forming a lengthy structure that is tightly packed in the form of chromosomes. Humans have 46 chromosomes organized into 23 pairs, including sex chromosomes.
Sequencing the human genome involves determining the order of these base pairs within DNA segments. This process has developed since the 1970s when methods for sequencing were first significantly advanced. The Human Genome Project, started in 1990, successfully sequenced the entire human genome, completing this project in 2003.
Key terms in genetics include SNPs (single nucleotide polymorphisms), which are variations at specific sites in the DNA that contribute to differences among individuals. These are classified as alleles, with most SNPs having two variations. Other variations include SNVs (single nucleotide variants) and microsatellites, which involve repeated segments of DNA.
The genotype refers to an organism's genetic information for a specific trait and can be represented by combinations of alleles. Genetic markers are often SNPs or microsatellites used in research to track genetic differences without influencing natural selection. Most DNA sites are noncoding, meaning they don’t directly influence traits, while genes are defined regions of DNA responsible for producing proteins.
It’s important to understand that most traits arise from the interaction of multiple genes rather than a single gene. Genetic drift refers to random changes in gene frequency that can occur in small populations, affecting the distribution of alleles over generations. These concepts are foundational for exploring how human populations can be analyzed through genetic profiles rather than physical traits.
Part II discusses how to think about differences between races. It starts by explaining that, while people accept major genetic differences related to sex, many believe that significant genetic differences in cognitive abilities across races are impossible. The goal is to show that it makes sense to expect some cognitive differences among races could be partly genetic. This idea is based on research done over the last 30 years. Important points include that human groups have unique genetic traits linked to their race, that evolution has changed populations since humans left Africa, and that genetic differences related to cognitive abilities among races are common. Each point will be explored further in the following chapters.
What the Orthodoxy Gets Right
The discussion points out that some ideas about race from history were wrong and that differences between races only make up a small part of human diversity. It agrees that while race is not completely meaningless, we should move away from the term "race" because it has a lot of negative history linked to racism and colonialism. Instead, it suggests using terms like "ancestral population" to more accurately describe genetic differences and our shared human history.
Third Interlude: Genetic Terms You Need to Know to Read the Rest of the Book
Genetic terminology is essential for understanding key concepts in genetics. A genome is made up of two strands of DNA arranged in a double helix found in the nucleus of cells. In humans, each DNA strand contains over three billion base pairs made from four chemicals: adenine (A), thymine (T), guanine (G), and cytosine (C). Base pairs are linked by hydrogen bonds, forming a lengthy structure that is tightly packed in the form of chromosomes. Humans have 46 chromosomes organized into 23 pairs, including sex chromosomes.
Sequencing the human genome involves determining the order of these base pairs within DNA segments. This process has developed since the 1970s when methods for sequencing were first significantly advanced. The Human Genome Project, started in 1990, successfully sequenced the entire human genome, completing this project in 2003.
Key terms in genetics include SNPs (single nucleotide polymorphisms), which are variations at specific sites in the DNA that contribute to differences among individuals. These are classified as alleles, with most SNPs having two variations. Other variations include SNVs (single nucleotide variants) and microsatellites, which involve repeated segments of DNA.
The genotype refers to an organism's genetic information for a specific trait and can be represented by combinations of alleles. Genetic markers are often SNPs or microsatellites used in research to track genetic differences without influencing natural selection. Most DNA sites are noncoding, meaning they don’t directly influence traits, while genes are defined regions of DNA responsible for producing proteins.
It’s important to understand that most traits arise from the interaction of multiple genes rather than a single gene. Genetic drift refers to random changes in gene frequency that can occur in small populations, affecting the distribution of alleles over generations. These concepts are foundational for exploring how human populations can be analyzed through genetic profiles rather than physical traits.