Biology 1010 Exam 4 Review

Chapters 10, 12, 13, 14

Locus

The physical location of a gene on a chromosome

True-Breeding

Always produced offspring resembling the parent plant for that trait; homozygous

Hybrids

Producing a mix of offspring for one or more traits; heterozygous

Dominant Allele

Encodes a protein that exerts its effects whenever it’s present

Recessive Allele

Encodes a protein whose effect is masked if a dominant allele is also present

Genotype

Expresses the genetic makeup of an individual, and it is written as a pair of letters representing the alleles

Homozygous

A gene has 2 identical alleles, meaning that both parents contributed the same gene version

Heterozygous

Possessing 2 different alleles for a particular gene, meaning that both parents contributed different genetic information

Phenotype

Observable characteristics of an organism

Wild-Type

Allele, genotype, or phenotype that is the most common form or expression of a gene in a population

Mutant

Allele, genotype, or phenotype variant that arises when a gene undergoes a mutation (not the most common, altered)

P-Generation (Parental/Purebred)

The first generation (true-breeding) in a genetic cross

F1-Generation (First/Filial)

The offspring of the P generation in a genetic cross

F2-Generation

The offspring of the F1 generation in a genetic cross

Monohybrid Cross

A mating between two individuals that are both heterozygous for the same gene

Punnett Square

A diagram that uses the genotypes of two parents to reveal which allele combinations their offspring may inherit

Law of Segregation

States that the two alleles of each gene are packaged into separate gametes; that is they “segregate” during gamete formation

Dihybrid Cross

Mating between two individuals that are both heterozygous for two genes

Test Cross

Mating between an individual of unknown genotype and a homozygous recessive individual

Law of Independent Assortment

During gene formation, the alleles for one gene do not influence the alleles for another gene

Product Rule

The probability that multiple independent events will occur simultaneously can be calculated by multiplying the chances of each event occurring alone

Linked Genes

Carried on the same chromosome; they are therefore inherited together. Unlike the genes on different chromosomes, they do not assort independently during meiosis

Linkage Groups

Collections of genes that tended to be inherited together

Crossing Over

An exchange of genetic information between homologous chromosomes during prophase 1 of meiosis

Parental chromatid

Chromatid containing genetic information from only one parent

Recombinant Chromatid

Carrying a mix of maternal and paternal alleles

Linkage Maps

Diagrams of gene order and spacing on chromosomes

Recombinant Offspring

An individual that inherits a recombinant chromatid