Question

Describe the type of information in a(n) a. empiric risk calculation. b. twin study. c. adoption study. d. genome-wide association study.

Short answer

An empiric risk calculation provides the observed probabilities of a certain outcome, usually a disease, in a population. Twin studies compare identical and fraternal twins to assess the impact of genetics versus environment on a trait. Adoption studies contrast adopted individuals to their biological and adoptive families to determine the relative contributions of genetics and environment. A genome-wide association study searches the entire genome for genetic variations associated with a certain trait.

Step-by-step solution

Empiric Risk Calculation

Empiric risk calculation offers the possibility of gaining information about the likelihood of developing a certain disease or trait based on the observation in a certain population or family. It is empirical because it is based on direct observations rather than theory.

Twin Study

Twin studies are used to analyze genetic and environmental influences on the development of a certain trait or disease, by comparing identical (monozygotic) twins who have the same genetic makeup and fraternal (dizygotic) twins who share about 50% of their genes.

Adoption Study

Adoption studies provide insight into the influence of genetic and environmental factors on the development of certain traits or diseases. By comparing adopted individuals to their biological and adoptive families, these studies can help determine how much a trait or disease is attributed to environmental effects versus genetic inheritance.

Genome-wide Association Study

A genome-wide association study (GWAS) investigates the entire genome to identify genetic variations or markers (often single nucleotide polymorphisms) associated with a certain trait or disease. It is a method used to examine many common genetic variants in different individuals to see if any variant is associated with a trait.

Key concepts

Empiric Risk Calculation

Empiric risk calculation is a technique used in genetics to determine the likelihood that an individual will develop a particular disease or display a certain trait. It's called 'empiric' because it relies on collected data from populations or families rather than theoretical risk estimates. The key is looking at the disease or trait prevalence within a defined group, and then calculating the risk based on relationships and the frequency of the condition.
For instance, if a disease is common among family members, the empiric risk for a relative to also develop the condition will be higher than in the general population. Empiric risk calculations help to inform individuals about their potential genetic health risks and can guide healthcare decisions.

Twin Study

Twin studies are a cornerstone of genetic research. These studies take advantage of the genetic relationship between monozygotic (identical) twins, who share nearly all their genes, and dizygotic (fraternal) twins, who share about 50% of their segregating genes. By comparing the traits and the incidence of diseases between these two types of twins, researchers can separate the influence of genetics from the environment.

For example, if a trait is more common in identical twins than in fraternal twins, it suggests a genetic component. Conversely, if the trait is equally common among both types of twins, it may point to environmental factors. Twin studies can reveal much about complex traits—those influenced by multiple genes and environmental factors.

Adoption Study

Adoption studies are unique in that they can separate environmental influences from genetic factors more clearly than many other study designs. By observing individuals who have been adopted and comparing their traits with those of their biological and adoptive parents, researchers can discern the effects of the environment versus heredity.
Consider a scenario where an adopted individual develops a disease that is prevalent in the biological family but not in the adoptive family. This scenario might suggest a stronger genetic basis for the disease. Conversely, if the disease is common in the adoptive family and not in the biological family, it might indicate an environmental cause. Adoption studies often help in the study of complex diseases like heart disease, diabetes, and psychological disorders, shedding light on the nature versus nurture debate.

Genome-wide Association Study (GWAS)

Genome-wide association studies (GWAS) explore the human genome in search of genetic variants associated with particular diseases or traits. Unlike research that focuses on a single gene, GWAS examines hundreds of thousands, or even millions, of genetic markers across the genome in large samples of individuals.
These studies can identify single nucleotide polymorphisms (SNPs), which are variations in a single DNA building block, correlated with diseases. If a certain SNP is found more frequently in people with a disease than in those without it, this SNP may be located near a gene involved in the disease. GWAS has been instrumental in uncovering genetic factors linked to complex diseases such as cancer, diabetes, and mental illnesses. It's an important tool for understanding the genetic underpinnings of diseases and for identifying potential targets for new treatments.