Sequence of DNA that encodes a specific protein or RNA molecule
one of two or more alternative forms of a gene
A continuous molecule of DNA wrapped around protein in the nucleus of a eukaryotic cell; also, the genetic material of a prokaryotic cell
A cell containing two full sets of chromosomes, one from each parent; also called 2n
A nonsex chromosome
A chromosome that carries genes that determine sex
Two chromosomes that look alike and have the same sequence of genes
Division of genetic material that halves the chromosome number and yields genetically variable nuclei
A cell containing one set of chromosomes; also called n
A sex cell; sperm or egg cell
The union of two gametes
Always producing offspring identical to the parent for one or more traits; homozygous
Producing a mix of offspring for one or more traits; heterozygous
Allele that is expressed whenever it is present
Allele whose expression is masked if a dominant allele is present
An individual’s combination of alleles for a particular gene
Possessing two identical alleles for a particular gene
Possessing two different alleles for a particular gene
Observable characteristic of an organism
The most common allele, genotype, or phenotype
An allele, genotype, or phenotype that is not the most common in a population or that has been altered from the “typical” (wild-type) condition
The first generation (true-breeding) in a genetic cross
The offspring of the P generation in a genetic cross
The offspring of the F1 generation in a genetic cross
The physical location of a gene on a chromosome
Mating between two individuals that are heterozygous for the same gene
Diagram that uses the genotypes of the parents to reveal the possible results of a genetic cross
A mating of an individual of unknown genotype to a homozygous recessive individual to reveal the unknown genotype
Mendel’s law stating that the two alleles of each gene are packaged into separate gametes
Mating between two individuals that are both heterozygous for one gene
Mendel’s law stating that during gamete formation, the segregation of the alleles for one gene does not influence the segregation of the alleles for another gene
The chance of two independent events occurring equals the product of the individual chances of each event
Genes on the same chromosome
Group of genes that tend to be inherited together because they are on the same chromosome
Exchange of genetic material between homologous chromosomes during prophase I of meiosis
Chromatid containing genetic information from only one parent
Chromatid containing genetic information from both parents as a result of crossing over
Diagram of gene order and spacing on a chromosome, based on crossover frequencies
An individual that inherits a recombinant chromatid
Mode of inheritance in which a heterozygote’s phenotype is intermediate between the phenotypes of the two homozygotes
Mode of inheritance in which two alleles are fully expressed in a heterozygote
Multiple, seemingly unrelated phenotypic effects of one genotype
One gene masks the phenotype associated with another gene
One allele masks the expression of another in a heterozygote
Describes genes or traits on the X or Y chromosome
Describes traits controlled by genes on the Y chromosome
Describes traits controlled by genes on the X chromosome
Turning off all but one X chromosome in each cell of a mammal (usually female) early in development
Inheritance pattern of a dominant allele on an autosome
Inheritance pattern of a recessive allele on an autosome
Chart showing family relationships and phenotypes
The study of changes in gene expression that do not involve changes in the DNA sequence
Caused by more than one gene; polygenic traits are typically expressed as a continuum of possible phenotypes