CH14 Mendel and the Gene Idea

What is genetics?

The scientific study of heredity and variation.

What does heredity refer to?

The transmission of traits from one generation to the next.

Who is known as the 'Father of Genetics'?

Gregor Mendel.

What is a character in genetics?

A heritable feature that varies among individuals.

What is a trait?

Each variant for a character.

What ratio did Mendel observe in the F2 generation of his monohybrid crosses?

A 3:1 ratio of dominant to recessive traits.

What is a monohybrid cross?

A cross that follows a single character, such as flower color.

What is the difference between a dominant and a recessive trait?

A dominant trait masks the effect of a recessive trait.

What is a gene?

A length of DNA coding for a particular protein.

What is an allele?

An alternative form of a gene.

What is a locus?

The position of a gene on a chromosome.

What is the Law of Segregation?

In a diploid organism, alleles for each trait segregate during gamete formation.

What is a Punnett square?

A diagram used to predict the genotypes and phenotypes of offspring.

What does the Law of Independent Assortment state?

Genes for different traits are inherited independently.

What is incomplete dominance?

A genetic scenario where traits blend together, producing a new phenotype.

What is codominance?

Both alleles affect the phenotype in separate, distinguishable ways.

What is epistasis?

When the phenotypic expression of one gene alters that of a gene at a second locus.

What is polygenic inheritance?

Inheritance involving more than one gene affecting a phenotype.

What are recessively inherited disorders?

Disorders where homozygous recessive individuals have the disease, while heterozygotes are carriers.

What is pleiotropy?

When one gene affects multiple phenotypic characters.

What is a karyotype?

An ordered display of chromosomes from a cell.

What are sex linked traits?

Sex-linked genes exhibit unique patterns of inheritance. X-linked recessive traits are transmitted via the X chromosome and affect males more frequently (e.g., hemophilia, colorblindness).

What is genetic testing?

The identification of carriers and affected individuals through various analyses.

How do Mendel's laws relate to chromosomes?

They have a physical basis in the behavior of chromosomes during meiosis.