Chromosomal Variation Flashcards
1
Q
Reverse Duplication
A
- Duplication of a chromosome segment in which the sequence of the duplicated segment is inverted relative to the sequence of the original segment.
2
Q
Segmental Duplication
A
- Duplicated chromosome segments larger than 1000 bp.
3
Q
Karyotype
A
- The complete set of chromosomes possessed by an organism; usually presented as a picture of a complete set of its metaphase chromosomes and arranged by length (longest to shortest).
4
Q
Tandem Duplication
A
- Chromosome rearrangement in which a duplicated chromosome segment is adjacent to the original segment.
5
Q
Displaced Duplication
A
- Chromosome rearrangement in which the duplicated segment is some distance from the original segment, either on the same chromosome or on a different one.
6
Q
Chromosome Duplication
A
- Mutation that doubles a segment of a chromosome.
7
Q
Chromosome Rearrangement
A
- Chromosome mutations that change the structures of individual chromosomes.
8
Q
Chromosome Mutation
A
- Variations in the number and structure of chromosomes; often affects many genes and has large phenotypic effects.
9
Q
Paracentric Inversion
A
- Chromosome inversion that does not include the centromere in the inverted region.
10
Q
Chromosome Inversion
A
- Rearrangement in which a segment of a chromosome has been inverted 180 degrees.
11
Q
Chromosome Deletion
A
- Loss of a chromosome segment.
12
Q
Dicentric Chromatid
A
- Chromatid that has two centromeres; produced when crossing over takes place within a paracentric inversion. The two centromeres of the dicentric chromatid are frequently pulled toward opposite poles in mitosis or meiosis, breaking the chromosome.
13
Q
Pericentric Inversion
A
- Chromosome inversion that includes the centromere in the inverted region.
14
Q
Acentric Chromatid
A
- Chromatid that lacks a centromere; produced when crossing over takes place within a paracentric inversion. The acentric chromatid does not attach to a spindle microtubule and does not segregate in meiosis or mitosis, so it is usually lost after one or more rounds of cell division.
15
Q
Translocation
A
- Movement of genetic material between nonhomologous chromosomes or within the same chromosome.
16
Q
Nondisjunction
A
- Failure of homologous chromosomes or sister chromatids to separate in meiosis or mitosis.
17
Q
Polyploidy
A
- Possession of more than two sets of chromosomes.
18
Q
Robertsonian Translocation
A
- Translocation in which the long arms of two acrocentric chromosomes become joined to a common centromere, generating a metacentric chromosome with two long arms and another chromosome with two very short arms.
19
Q
Nonreciprocal Translocation
A
- Movement of a chromosome segment to a nonhomologous chromosome or chromosomal region without any (or with unequal) reciprocal exchange of segments.
20
Q
Reciprocal Translocation
A
- Reciprocal exchange of segments between two nonhomologous chromosomes.
21
Q
Aneuploidy
A
- Change in the number of individual chromosomes; most often an increase or a decrease of one or two chromosomes.
22
Q
Nullisomy
A
- Absence of both members of a homologous pair of chromosomes (2n - 2).
23
Q
Allopolyploidy
A
- Condition in which all chromosomes of a polyploid individual are from two or more species.
24
Q
Monosomy
A
- Absence of one of the chromosomes of a homologous pair.
25
Q
Tetrasomy
A
- Presence of two extra copies of a chromosome (2n + 2)
26
Q
Trisomy
A
- Presence of an extra copy of a chromosome (2n + 1).
27
Q
Dosage Compensation
A
- A mechanism to equalize the amount of protein produced by X-linked genes and autosomal genes. In placental mammals, dosage compensation is accomplished by the random inactivation of one X chromosome in the cells of females.
28
Q
Autopolyploidy
A
- Condition in which all the sets of chromosomes of a polyploid individual are derived from a single species.
29
Q
Unbalanced Gametes
A
- Gamete that has a variable number of chromosomes; some chromosomes may be missing and others may be present in more than one copy.
