Intro to Genetics Quiz

Gene

the basic unit of information affecting a genetic trait

Mutation

any change in the DNA sequence that makes up a gene

Genetic Trait

any inherited characteristic of an organism

Invariant traits

traits are the same in all individuals of the species

Physical traits

easily observable traits (shape of a dogs face)

Biochemical traits

often more difficult to observe (lactase persistence)

Behavioral Traits

behaviors with some genetic basis (introversion and extroversion)

Phenotype

the physical expression of a given trait

Genotype

he pair of alleles for a given trait that codes for the phenotype

Dominant

one allele that prevents a second allele from affecting the phenotype when two alleles are paired together

Recessive

an allele that has no effect on the phenotype when paired with a dominant allele

Heterozygous

The genotype consist of two different alleles (Bb Cc)

Homozygous

the genotype consists of two copies of the same allele (BB, bb, CC,)

Who is known as the 'father of genetics'?

Gregor Mendel

What type of plants did Gregor Mendel breed?

Pea plants

What is a genetic cross?

A controlled mating experiment to examine how a particular trait is inherited

P generation

the organisms in the first cross ("p" for parental) one parent is homozygous dominant (PP) the other is homozygous recessive (pp).

F1 Generation

("F:" for filial") the first generation of offspring mendel observed

F2 Generation

The offspring resulting when individuals of the F1 generation are crossed with each other

Mendel's careful expirement

Mendel manipulated the P generation plants by removing all the female structures from one plant and all the male structures from the other, thus preventing self-fertilization. He could then perform the initial cross by transferring pollen from the "male" plant to the flower of the "female" plant.

Punnett Square

a grid-like diagram used to predict the results of a genetic cross

Mendel's 3 Laws

The Law of Segregation, The Law of Independent Assortment, and The Law of Dominance

The Law of Segregation

The two alleles of a gene are separated during meiosis I and end up in different gametes. Can be used to predict how a single trait will be inherited from the genes of two parents.

The Law of Independent Assortment

When gametes form, the two alleles of any given gene segregate during meiosis independently of any two alleles of other genes.

The Law of Dominance

When two alleles for contrasting traits are present, the offspring will exhibit only the dominant trait

What is the term for the inheritance of alleles of two different genes independently from each other?

Independent Assortment

What type of breeding experiments did Mendel use to test the hypothesis of independent assortment?

Dihybrid crosses

Mendelian traits

controlled by a single gene and unaffected by environmental conditions

Incomplete Dominance

Situation in which one allele is not completely dominant over another allele. Ex: LS makes medium sized dog.

Codominance

when the effects of the 2 alleles are equally visible in the phenotype of the heterozygote. BW Black and White checkered of feathered chickens.

Complex Traits

a genetic trait whose pattern of inheritance cannot be predicted by mendel's laws and don't fit the straightforward single gene, single phenotype pattern.

Pleiotropy

when a single gene influences a number of different traits. Ex: The shape of a dog's head and the shape of its limb bones are controlled by a single gene.

Polygenic traits

single traits governed by more than one gene. Ex: in humans Eye color, Skin color Body Size, are all polygenic traits that are controlled by more than one gene.

Epistasis

Two genes are inherited independently but the alleles of one gene affect the expression of the other gene's alleles. Ex: Coat color or mice or Labrador retrievers.