Alleles
An alternative version of a gene
Carrier
An individual who is heterozygous for a recessively inherited disorder and who therefore does not show symptoms of that disorder
Codon
A three-nucleotide sequence in mRna that specifies a particular amino acid or polypeptide termination signal; basic unit of the genetic code
Codominant
Expressing two different alleles of a gene in a heterozygote
Dihybrid cross
A mating of individuals differing at two genetic loci
DNA
Deoxyribonucleic acid; The genetic material that organisms inherit from their parents
Dominant Allele
In a heterozygote, the allele that determines the phenotype with respect to a particular gene
Exons
In eukaryotes, a coding portion of a gene
F1 Generation
The offspring of two parental individuals (stands for first filial)
F2 Generation
The offspring of the F1 generation (stands for second filial)
Genetics
The scientific study of heredity
Genotype
The genetic makeup of an organism
Heredity
The transmission of traits from one generation to the next
Heterozygous
Having two different alleles for a given gene
Homozygous
Having two identical alleles for a given gene
Hybrid
The offspring of parents of two different species or of two different varieties of one species
Incomplete Dominance
A type of inheritance in which the phenotype of a heterozygote is intermediate between the phenotypes of the two types of homozygotes
Introns
In eukaryotes, a nonexpressed portion of a gene that is excised from the RNA transcript
Law of independent assortment
A general rule of inheritance, first proposed by Gregor Mendel, that states that when gametes form during meiosis, each pair of alleles for a particular character segregate independently of each other pair
Law of segregation
A general rule of inheritance, first proposed by Gregor Mendel, that states that the two alleles in a pair segregate into different gametes during meiosis
Linked genes
Genes located close enough together on a chromosome that they are usually inherited together
Locus
The particular site where a gene is found on a chromosome
Messenger RNA (mRNA)
The type of ribonucleic acid that encodes genetic information from DNA and conveys it to ribosomes, where the information is translated into amino acid sequences
Monohybrid Cross
A mating of individuals differing at one genetic locus
Mutagen
A chemical or physical agent that interacts with DNA and causes a mutation
Mutation
A change in the nucleotide sequence of DNA; a major source of genetic diversity
Nucleotide
An organic monomer consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group (building blocks of nucleic acids)
Pedigree
A family tree representing the occurrence of heritable traits in parents and offspring across a number of generations
P generation
The parent individuals from which offspring are derived in studies of inheritance. P stands for parental
Phenotype
The expressed traits of an organism
Pleiotropy
The control of more that one phenotypic character by a single gene
Polygenic inheritance
The additive effect of two or more genes on a single phenotypic characteristic
Punnett Square
A diagram used in the study of inheritance to show the results of random fertilization
Recessive Allele
In Heterozygotes, the allele that has no noticeable effect on the phenotype
sex-linked gene
A gene located on a sex chromosome
Trait
A variant of a character found within a population, such as purple flowers in pea plants
Transcription
The synthesis of RNA on a DNA Template
Translation
The synthesis of a polypeptide using the genetic information encoded in an mRNA Molecule