Chapter 8 Flashcards
A chromosomal alteration in which the gene dosage is changed
Unbalanced
A type of unbalanced chromosomal alteration in which part of a chromosome is doubled
Duplication
A type of unbalanced chromosomal alteration in which part of a chromosome is lost
Deletion
A chromosomal alteration in which the gene dosage is not changed
Balanced
A type of balanced chromosomal alteration in which the gene order on part of a chromosome is reversed, occurs when chromosomes break and are reattached in the wrong orientation
Chromosome Inversion
A type of balanced chromosomal alteration in which part of a chromosome is moved to another chromosome, occurs when a chromosome breaks and is reattached to a non-homologous chromosome
Chromosome Translocation
Multi-gene families generated by duplications in which duplicated copies can evolve new functions and expression patterns
Paralogs
A gene where the mutant phenotype occurs only when one copy of the gene is present
Haploinsufficient gene
Recombination at misaligned chromatids, usually occurs with sequences that are very similar
Unequal Crossing Over
A type of chromosome inversion in which the inverted portion involves only one chromosome arm (does not occur across the centromere)
Paracentric Inversion
A type of chromosome inversion that occurs when the inverted portion involves both chromosome arms (occurs across the centromere)
Pericentric Inversion
When crossing over occurs, but the only viable offspring are recombinant. Usually occurs when crossing over occurs within the inversion, meaning inversion heterozygotes have reduced fertility
Crossover Suppression
One of the three types of translocation, in which pieces on two non-homologous chromosomes switch places
Reciprocal Translocation
One of the three types of translocations in which a piece of one chromosomes is translocated to a nonhomologous chromosome
Nonreciprocal Translocation
When homologs segregate to opposite daughter cells
Disjunction
When homologs are retained together in the same daughter cell
Nondisjunction
A pattern of meiotic segregation in a reciprocal translocation heterozygote in which it is balanced and there is disjunction
Alternate
A pattern of meiotic segregation in a reciprocal translocation heterozygote in which it is unbalanced and there is disjunction
Adjacent-1
A pattern of meiotic segregation in a reciprocal translocation heterozygote in which it is unbalanced and there is nondisjunction
Adjacent-2
One of the three types of translocation in which two breaks occur on non-homologous chromosomes with reciprocal exchange between acrocentric chromosomes, results in the total number of chromosomes being reduced by 1
Robertsonian Translocation
The number of chromosomes in a basic set of chromosomes
Monoploid
When each organism contains multiples of the basic chromosome set
Euploid
The number of chromosome sets
Ploidy
The number of chromosome present in gametes, always 1/2 the total number of chromosomes
Haploid
Incomplete sets of chromosomes, results from a change in the number of individual chromosomes
Aneuploidy
A type of aneuploidy, 2n-2
Nullisomy
A type of aneuploidy, 2n-1
Monosomy
A type of aneuploidy, 2n+1
Trisomy
A type of aneuploidy, 2n+2
Tetrasomy
When two homologous chromosomes or chromatids segregate to the same pole, can occur in meiosis 1 or meiosis 2
Nondisjunction
A type of down syndrome (95% of cases) that results from nondisjunction during meiosis 1 in females
Primary Down Syndrome
A type of down syndrome (5% of cases) that results from a Robertsonian translocation between chromosomes 14 and 21.
Familial Down Syndrome
The basic chromosome number of a single, complete set of non-homologous chromosomes, not the same as n in polyploids
x (monoploid) number
More than the normal number of complete sets of chromosomes, results from a rare genome doubling
Polyploidy
3x polyploidy
Triploid
4x polyploidy
Tetraploid
5x polyploidy
Pentaploid
6x polyploidy
Hexaploid
Polyploids derived from a single species, results from nondisjunction during mitosis in 2n cells of an early embryo (autotetraploid) or nondisjunction during meiosis that produces a diploid gamete that is fertilized with a 1n gamete (autotriploid)
Autopolyploids
Polyploids derived from two or more species, results from the union of haploid gametes from two different species followed by chromosome doubling
Allopolypoids