Chapter 14: Mendel and the Gene Idea

Flashcards covering key concepts from Mendel's principles of genetics, inheritance patterns, and vocabulary relevant to the study of heredity.

Heredity

The process by which genetic information is passed on from parent to child.

Monohybrid Cross

A genetic cross between parents that differ in only one characteristic.

Dihybrid Cross

A genetic cross between parents that differ in two characteristics.

Genotype

The combination of alleles found in an individual.

Phenotype

An individual's observable traits.

Homozygous

Individuals with two copies of the same allele (e.g., RR or rr).

Heterozygous

Individuals with two different alleles (e.g., Rr).

Dominant Allele

An allele that produces its phenotype in both homozygous and heterozygous individuals.

Recessive Allele

An allele that produces its phenotype only in homozygous individuals.

Independent Assortment

The principle that alleles for different traits segregate independently of one another during gamete formation.

Segregation Principle

The principle stating that two members of each gene pair must segregate from each other during gamete formation.

Linkage

The tendency of genes located on the same chromosome to be inherited together.

Codominance

A situation in which both alleles in a heterozygote contribute to the phenotype.

Incomplete Dominance

A situation where heterozygotes display an intermediate phenotype.

Pleiotropic Genes

Genes that influence multiple phenotypic traits.

Environmental Influence on Phenotype

The effect that environmental factors have on the expression of genetic traits.

Quantitative Traits

Traits that are controlled by multiple genes and show continuous variation.

Pedigree Analysis

A family tree diagram that shows the inheritance of traits over generations.

Test Cross

A cross between an individual with an unknown genotype and a homozygous recessive individual to determine the genotype.

X-linked Inheritance

Inheritance patterns associated with genes located on the X chromosome.

Autosomal Inheritance

Inheritance patterns associated with genes not located on sex chromosomes.

Multiple Alleles

The presence of more than two alleles for a genetic trait within a population.

Epistasis

A phenomenon where the expression of one gene is affected by the presence of another gene.

Punnett Square

A diagram used to predict the outcome of a genetic cross.

Locus

The specific physical location of a gene on a chromosome.

Allele Frequency

The proportion of a specific allele within a population.

Wild Type Allele

The most common allele in a population, often considered the "normal" allele.

Mutant Allele

An allele that has been altered by mutation, typically rarer than the wild-type allele.

Genomic Imprinting

A phenomenon where the expression of a gene depends on whether it was inherited from the mother or the father.

Mitochondrial Inheritance

A non-Mendelian inheritance pattern where traits are passed down from the mother to all her offspring due to genes located in the mitochondria.

Genetic Mapping

The process of determining the relative locations of genes on a chromosome and the distances between them.

Recombination Frequency

The measure of genetic linkage, indicating the percentage of recombinant offspring in a dihybrid cross.

Nondisjunction

The failure of homologous chromosomes or sister chromatids to separate properly during meiosis or mitosis.

Aneuploidy

A condition in which a cell contains an abnormal number of chromosomes, resulting from nondisjunction (e.g., Trisomy 21).

Gene Expression

The process by which information from a gene is used in the synthesis of a functional gene product, such as a protein or RNA.

Punnett Square

A diagram used to predict the outcome of a genetic cross.

Locus

The specific physical location of a gene on a chromosome.

Allele Frequency

The proportion of a specific allele within a population.

Wild Type Allele

The most common allele in a population, often considered the "normal" allele.

Mutant Allele

An allele that has been altered by mutation, typically rarer than the wild-type allele.

Genomic Imprinting

A phenomenon where the expression of a gene depends on whether it was inherited from the mother or the father.

Mitochondrial Inheritance

A non-Mendelian inheritance pattern where traits are passed down from the mother to all her offspring due to genes located in the mitochondria.

Genetic Mapping

The process of determining the relative locations of genes on a chromosome and the distances between them.

Recombination Frequency

The measure of genetic linkage, indicating the percentage of recombinant offspring in a dihybrid cross.

Nondisjunction

The failure of homologous chromosomes or sister chromatids to separate properly during meiosis or mitosis.

Aneuploidy

A condition in which a cell contains an abnormal number of chromosomes, resulting from nondisjunction (e.g., Trisomy 21).

Gene Expression

The process by which information from a gene is used in the synthesis of a functional gene product, such as a protein or RNA.