Biology Chapter on Epigenetics and Inheritance

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Questions and Answers

Define epigenetics.

Stable gene expression changes without DNA sequence alteration.

What is gene expression?

The process of DNA transcribing to RNA to protein.

What is gene regulation?

Transient changes in gene expression due to environmental signals.

What is epigenetic inheritance?

Inheritance of epigenetic states from parents to offspring. Signup and view all the answers

Describe X-Chromosome Inactivation.

Random inactivation of one X chromosome in females. Signup and view all the answers

What is a Barr body?

Condensed, inactive X chromosome visible in females. Signup and view all the answers

Explain the phenomenon of calico cats.

Female cats with random X inactivation producing color patches. Signup and view all the answers

Define extranuclear inheritance.

Transmission of genes located outside the nucleus. Signup and view all the answers

What are organelle genomes?

Genomes found in mitochondria and chloroplasts. Signup and view all the answers

What does the mitochondrial genome contain?

Contains 37 genes essential for cellular respiration. Signup and view all the answers

What is LHON?

Leber's hereditary optic neuropathy causing vision loss. Signup and view all the answers

Define gene linkage.

Genes close together on the same chromosome inherited together. Signup and view all the answers

Explain what a linkage group is.

A group of genes that usually stay together during meiosis. Signup and view all the answers

What are recombinants?

Offspring with different traits from parental generation. Signup and view all the answers

What is linkage mapping?

Mapping genes based on recombination frequencies. Signup and view all the answers

What is recombination frequency?

Percentage of recombinant offspring in a cross. Signup and view all the answers

Define CentiMorgan (cM).

Unit of genetic distance; 1% recombination frequency. Signup and view all the answers

What is vernalization?

Cold temperatures required for flowering in plants. Signup and view all the answers

What is the function of the FLC gene?

Gene whose expression is silenced during vernalization. Signup and view all the answers

Describe mitochondrial diseases.

Diseases inherited maternally affecting energy production. Signup and view all the answers

What is the chloroplast genome?

Genome affecting chlorophyll synthesis and leaf color. Signup and view all the answers

What is gene silencing?

Turning off gene expression through epigenetic changes. Signup and view all the answers

What is dosage compensation?

Equal expression of X-linked genes in males and females. Signup and view all the answers

Define a mosaic.

Individual with genetically different somatic cells. Signup and view all the answers

What are environmental agents?

Factors influencing epigenetic changes in gene expression. Signup and view all the answers

Define phenotype.

Observable traits resulting from gene expression. Signup and view all the answers

Study Notes

Epigenetics

Epigenetics involves stable changes in gene expression without altering the DNA sequence.
Gene expression is the process of DNA transcribing to RNA to protein.
Gene regulation is the transient changes in gene expression due to environmental signals.
Epigenetic inheritance is the transmission of epigenetic states from parents to offspring.

X-Chromosome Inactivation

X-Chromosome inactivation is the random inactivation of one X chromosome in females.
The inactive X chromosome forms a Barr body, a visible condensed structure.
Calico cats exhibit a classic example of X-inactivation, resulting in color patches.

Extranuclear Inheritance

Extranuclear inheritance involves the transmission of genes outside the nucleus, specifically in organelles like mitochondria and chloroplasts.
Organelle genomes include mitochondrial and chloroplast genomes.
The mitochondrial genome contains genes crucial for cellular respiration (37 genes).
Leber's hereditary optic neuropathy (LHON) is a maternally inherited mitochondrial disease causing vision loss.

Gene Linkage and Mapping

Gene linkage describes how genes located close together on the same chromosome tend to be inherited together.
A linkage group refers to genes usually inherited together during meiosis.
Recombinants are offspring with traits different from parental traits due to crossing over.
Nonrecombinants are offspring with unchanged traits inherited from their parents.
Linkage mapping determines distances between genes based on recombination frequencies.
Recombination frequency is the percentage of recombinant offspring in a cross.
CentiMorgans (cM) are units of genetic distance, equal to 1% recombination frequency.

Other Concepts

Vernalization is the requirement of cold temperatures for flowering in plants.
The FLC gene's expression is silenced during vernalization.
Mitochondrial diseases affect energy production and are often maternally inherited.
Chloroplast genomes influence chlorophyll synthesis and leaf color.
Gene silencing is the process of turning off gene expression via epigenetic mechanisms.
Dosage compensation ensures equal expression of X-linked genes in males and females.
A mosaic is an individual with genetically different somatic cells.
Environmental agents influence epigenetic changes affecting gene expression and phenotype.
Phenotype refers to the observable traits resulting from gene expression.

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Description

This quiz explores key concepts in epigenetics, including gene expression, gene regulation, and epigenetic inheritance. It also covers X-chromosome inactivation and extranuclear inheritance, emphasizing their biological significance and examples like calico cats. Test your knowledge of these fascinating topics in genetics!