CHAPTER 8 Variation in Chromosome Structure and Number
Acentric Fragment Fragment of a chromosome that lacks a centromere
Acrocentric Chromosome with the centromere significantly off
center, but not at the end
Allelic Variation Genetic variation in a population that involves the
occurrence of two or more different alleles for a
particular gene
Balanced Translocation Translocation in which the total amount of genetic
material remains (nearly) normal
Centromere Segment of a eukaryotic chromosome that provides an
attachment site for the kinetochore
Comparative Genomic Hybridization technique to determine if cells have
Hybridization (CGH) changes in chromosome structure, such as deletions or
duplications
Complete Nondisjunction Event in which all of the chromosomes fail to segregate
properly during meiosis/mitosis and remain in one of
the two daughter cells
Copy Number Variation (CNV) Type of structural variation in which a segment of DNA
that is 1.000 bp or more in length commonly exhibits
copy number differences among members of the same
species
Deficiency Condition in which a segment of chromosomal material
is missing
Deletion Condition in which a segment of DNA is missing
Dicentric Bridge The region between the two centromeres in a dicentric
chromosome
Dicentric Chromosome Chromosome with two centromeres
Duplication The repetition of a segment of DNA more than once
within a chromosome and/or within a genome
Euploid Organism in which the chromosome number is an exact
multiple of a chromosome set
Acentric Fragment Fragment of a chromosome that lacks a centromere
Acrocentric Chromosome with the centromere significantly off
center, but not at the end
Allelic Variation Genetic variation in a population that involves the
occurrence of two or more different alleles for a
particular gene
Balanced Translocation Translocation in which the total amount of genetic
material remains (nearly) normal
Centromere Segment of a eukaryotic chromosome that provides an
attachment site for the kinetochore
Comparative Genomic Hybridization technique to determine if cells have
Hybridization (CGH) changes in chromosome structure, such as deletions or
duplications
Complete Nondisjunction Event in which all of the chromosomes fail to segregate
properly during meiosis/mitosis and remain in one of
the two daughter cells
Copy Number Variation (CNV) Type of structural variation in which a segment of DNA
that is 1.000 bp or more in length commonly exhibits
copy number differences among members of the same
species
Deficiency Condition in which a segment of chromosomal material
is missing
Deletion Condition in which a segment of DNA is missing
Dicentric Bridge The region between the two centromeres in a dicentric
chromosome
Dicentric Chromosome Chromosome with two centromeres
Duplication The repetition of a segment of DNA more than once
within a chromosome and/or within a genome
Euploid Organism in which the chromosome number is an exact
multiple of a chromosome set
