Term
|
Definition
| A change in the number of chromosomes that can lead to a chromosomal abnormality. |
|
|
Term
|
Definition
| The presence of three copies, instead of the normal two, of a particular chromosome. The presence of an extra chromosome 21, which is found in Down syndrome, is called trisomy 21. |
|
|
Term
|
Definition
| Occurs in cells and organisms when there are more than two homologous sets of chromosomes. Most organisms are normally diploid; polyploidy may occur due to abnormal cell division. |
|
|
Term
|
Definition
| A chromosome rearrangement in which a segment of a chromosome is reversed end to end. An inversion occurs when a single chromosome undergoes breakage and rearrangement within itself. |
|
|
Term
|
Definition
| An inversion in which the breakpoints are confined to one arm of a chromosome; a chromosomal inversion that does not include the centromere. |
|
|
Term
|
Definition
| An inversion that includes the centromere and there is a break point in each arm. |
|
|
Term
|
Definition
| A chromosome abnormality caused by rearrangement of parts between nonhomologous chromosomes. |
|
|
Term
|
Definition
Any duplication of a region of DNA that contains a gene; it may occur as an error in homologous recombination, a retrotransposition event, or duplication of an entire chromosome. |
|
|
Term
|
Definition
| a mutation (a genetic aberration) in which a part of a chromosome or a sequence of DNA is missing. Deletion is the loss of genetic material. Any number of nucleotides can be deleted, from a single base to an entire piece of chromosome. Deletions can be caused by errors in chromosomal crossover during meiosis. |
|
|
Term
|
Definition
| A segment of a chromosome that lacks a centromere. |
|
|
Term
|
Definition
| An aberrant chromosome having two centromeres. |
|
|
Term
|
Definition
| A mutant strain of an organism that cannot synthesize essential molecules required for things such as growth. If this is the case it must have the molecule supplied in the growth medium for it to grow. |
|
|
Term
|
Definition
| A strain of an organism that is wild-type for all nutritional requirements and can grow on a minimal medium ( A minimal medium contains only the nutrients required for the growth of wild-type cells.) |
|
|
Term
|
Definition
chromosomes in a biological cell that pair (synapse) during meiosis . |
|
|
Term
|
Definition
| : DNA that a bacterial cell has taken up through one of its sexual processes. |
|
|
Term
|
Definition
| Bacterial host chromosome |
|
|
