Podcast
Questions and Answers
What is the main factor that contributes to the development of disorders like attention-deficit/hyperactivity disorder?
What is the main factor that contributes to the development of disorders like attention-deficit/hyperactivity disorder?
- Epigenetic variation
- Environmental factors
- Inherited predisposition
- Interaction between inherited predisposition and environmental factors (correct)
What is the primary reason why identical twins, despite having the same genetic code, look and act slightly different?
What is the primary reason why identical twins, despite having the same genetic code, look and act slightly different?
- Inherited predisposition
- Epigenetic variation (correct)
- Environmental factors
- Different DNA sequences
What is the term used to describe the study of biochemical modifications of genetic expression that do not alter DNA sequence?
What is the term used to describe the study of biochemical modifications of genetic expression that do not alter DNA sequence?
- Epigenetics (correct)
- Genetics
- Biochemical modification
- Epigenesis
What are the chemical molecules that affect the way a cell reads a gene's DNA?
What are the chemical molecules that affect the way a cell reads a gene's DNA?
What is the function of the chemical tags in epigenesis?
What is the function of the chemical tags in epigenesis?
What can cause epigenetic changes, according to the text?
What can cause epigenetic changes, according to the text?
What are some common ailments that epigenetic changes can contribute to?
What are some common ailments that epigenetic changes can contribute to?
What is the phenomenon where certain genes are turned off or on as they are needed by the developing body or triggered by the environment?
What is the phenomenon where certain genes are turned off or on as they are needed by the developing body or triggered by the environment?
What type of correlation occurs when a child's genetic makeup influences their environment?
What type of correlation occurs when a child's genetic makeup influences their environment?
What is the term for the tendency of certain genetic and environmental influences to reinforce each other?
What is the term for the tendency of certain genetic and environmental influences to reinforce each other?
In which scenario does a passive correlation occur?
In which scenario does a passive correlation occur?
What is the result of reactive correlation in the example of a child who shows interest and ability in music?
What is the result of reactive correlation in the example of a child who shows interest and ability in music?
What is the term for the study of the genetic and environmental factors that influence behavior?
What is the term for the study of the genetic and environmental factors that influence behavior?
What type of correlation occurs when a child's environment is influenced by their biological parents, but the child does not control it?
What type of correlation occurs when a child's environment is influenced by their biological parents, but the child does not control it?
What percentage of inheritance is associated with certain rare physical disorders?
What percentage of inheritance is associated with certain rare physical disorders?
What is the main goal of the science of behavioral genetics?
What is the main goal of the science of behavioral genetics?
What is heritability?
What is heritability?
What is the concept used to study the influence of heredity and environment on traits?
What is the concept used to study the influence of heredity and environment on traits?
Why is it important to study the influence of heredity and environment on traits?
Why is it important to study the influence of heredity and environment on traits?
What is the relationship between heredity and environment in shaping traits?
What is the relationship between heredity and environment in shaping traits?
How is heritability measured?
How is heritability measured?
What is the limitation of heritability?
What is the limitation of heritability?
What is the primary reason why defects transmitted by recessive genes tend to be lethal at an earlier age?
What is the primary reason why defects transmitted by recessive genes tend to be lethal at an earlier age?
What is the result of the presence of a dominant/recessive gene pair in a person's genome?
What is the result of the presence of a dominant/recessive gene pair in a person's genome?
What is the primary characteristic of alpha thalassemia?
What is the primary characteristic of alpha thalassemia?
Which genetic disorder is most commonly found in males and is marked by muscle weakness and minor intellectual disability?
Which genetic disorder is most commonly found in males and is marked by muscle weakness and minor intellectual disability?
What is the typical outcome for infants with anencephaly?
What is the typical outcome for infants with anencephaly?
What is the primary treatment for hemophilia?
What is the primary treatment for hemophilia?
What is the characteristic of spina bifida?
What is the characteristic of spina bifida?
Which genetic disorder is typically found in families of Mediterranean descent?
Which genetic disorder is typically found in families of Mediterranean descent?
What is the typical outcome for people with cystic fibrosis?
What is the typical outcome for people with cystic fibrosis?
Why can recessive genes be transmitted to the next generation?
Why can recessive genes be transmitted to the next generation?
What is the main reason why highly canalized traits tend to be predictable and reliable?
What is the main reason why highly canalized traits tend to be predictable and reliable?
What is the characteristic of highly canalized traits in terms of their expression?
What is the characteristic of highly canalized traits in terms of their expression?
What is the purpose of natural selection in designing highly canalized traits?
What is the purpose of natural selection in designing highly canalized traits?
What is an example of a highly canalized trait in humans?
What is an example of a highly canalized trait in humans?
Why are highly canalized traits less susceptible to environmental influences?
Why are highly canalized traits less susceptible to environmental influences?
What is the role of genetics in the development of highly canalized traits?
What is the role of genetics in the development of highly canalized traits?
What is the consequence of a highly canalized trait being influenced by an extreme change in environment?
What is the consequence of a highly canalized trait being influenced by an extreme change in environment?
What is the main difference between highly canalized traits and other traits?
What is the main difference between highly canalized traits and other traits?
Study Notes
Epigenetic Influences on Gene Expression
- Epigenetic variation can explain why identical twins, who share 100% of their genetic code, look and act slightly different.
- Epigenetic influences involve biochemical modifications of genetic expression "above the genome" without altering DNA sequence.
- Epigenesis works via chemical molecules, or "tags," attached to a gene that affect the way a cell "reads" the gene's DNA.
- Environmental factors, such as nutrition, smoking, sleep habits, stress, and physical activity, can cause epigenetic changes.
Inheritance and Genetic Disorders
- Many disorders arise from the interaction between an inherited predisposition (an abnormal variant of a normal gene) and an environmental factor.
- Recessive genes are not expressed if the parent is heterozygous for that trait, and may not be apparent that a child is at risk for receiving two alleles of a recessive gene.
- Defects transmitted by recessive genes tend to be lethal at an earlier age, in contrast to those transmitted by dominant genes.
- Examples of genetic disorders include:
- Alpha thalassemia: severe anemia, primarily affects families of Malaysian, African, and Southeast Asian descent.
- Beta thalassemia (Cooley's anemia): severe anemia, primarily affects families of Mediterranean descent.
- Cystic fibrosis: overproduction of mucus, affects 1 in 2,000 White births.
- Duchenne muscular dystrophy: fatal disease, usually found in males, marked by muscle weakness and minor intellectual disability.
- Hemophilia: excessive bleeding, usually affects males, affects 1 in 10,000 families with a history of hemophilia.
- Anencephaly: absence of brain tissues, affects 1 in 1,000 births.
- Spina bifida: incompletely closed spinal canal, affects 1 in 1,000 births.
Correlation between Genotype and Environment
- Genotype-environment correlation: the tendency of certain genetic and environmental influences to reinforce each other.
- Passive correlations: correlations between genotype and environment that are beyond the child's control, applicable to young children.
- Reactive correlations: correlations between genotype and environment where children evoke different reactions from others based on their genetic makeup.
Behavioral Genetics
- Behavioral genetics: the study of the relative influences of heredity and environment on behavior.
- Heritability: a statistical estimate of the contribution of heredity to individual differences in a specific trait within a given population.
- Heritability cannot be measured directly, but can be estimated by studying groups of people with known genetic relationships.
- Canalized traits: traits that are strongly programmed by genes and have little opportunity for variance in their expression, such as those necessary for survival.
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Description
Explore the relationship between inherited predispositions, environmental factors, and epigenetic variations. Learn how identical twins with the same genetic code can exhibit differences.
