Module 7 Flashcards
True breeding
If an organism has a certain characteristic that is always passed on to its offspring, we say that this organism bred true with respect to that characteristic.
Allele
One of a pair of genes that occupies the same position on homologous chromosomes
Genotype
Two-letter set that represents the alleles an organism possesses for a certain trait
Phenotype
The observable expression of an organism’s genes
Homozygous genotype
A genotype in which both alleles are identical
Heterozygous genotype
A genotype with two different alleles
Dominant allele
An allele that will determine phenotype if just one is present in the genotype
Recessive allele
An allele that will not determine the phenotype unless the genotype is homozygous in that allele
Testcross
Breeding an organism displaying the dominant phenotype but unknown genotype with a homozygous recessive organism
Pedigree
A diagram that follows a particular phenotype through several generations
Monohybrid cross
A cross between two individuals, concentrating on only one definable trait
Dihybrid cross
A cross between two individuals, concentrating on two definable traits
Autosomes
Chromosomes that do not determine the sex of an individual
Sex chromosomes
Chromosomes that determine the sex of an individual
Carriers
Individuals who have one copy of an allele for a recessive trait but do not exhibit the trait
Incomplete dominance
Inheritance pattern in which heterozygotes have a phenotype intermediate between the phenotypes of the homozygotes
Codominance
Inheritance pattern in which heterozygotes express the distinct phenotypes of both alleles
Antigen
A substance that, when introduced into the blood, triggers the production of an antibody
Antibody
Specialized proteins in your immune system used to attack and destroy specific antigens
Sex-linked inheritance
Inheritance of a genetic trait located on the sex chromosomes
Gene mutation
A radical change in the DNA of one or more alleles
Chromosomal mutations
Changes in the chromosome structure in which a chromosome loses or gains genes during meiosis
Nondisjunction
A situation in which abnormal cellular events in meiosis lead to either none of a particular chromosome in the gamete or more than one of a particular chromosome in the gamete
Genome
A complete set of an organism’s genetic information encoded in its DNA
Short tandem repeats (STRs)
Short sequences of DNA (usually from two to six base pairs in length) that are repeated numerous times at various locations in the noncoding region of a chromosome
Restriction enzyme
An enzyme that recognizes and cuts DNA only at a specific sequence of nucleotides
Plasmid
A small, circular section of extra DNA that confers one or more traits to a bacterium and can be reproduced separately from the main bacterial genetic code
Recombinant DNA
Taking DNA from two different species and combining them in one cell
Genetically modified organism
An organism that has been genetically altered by humans
Transgenic organism
An organism that carries one or more genes from a different species
Transgenic organism
An organism that carries one or more genes from a different species
