Term
|
Definition
| addition of 1 or more complete sets of chromosomes to the genome |
|
|
Term
|
Definition
| multiplication of 1 set of chromosomes (same species). Results from a lack of disjunction between all chromosomes during meiosis. |
|
|
Term
|
Definition
| combination of 2 different sets of chromosomes (different species). Example: common wheat |
|
|
Term
|
Definition
| an ancient polyploid that is no longer recognizable. It looks like a diploid |
|
|
Term
| Is yeast an ancient tetraploid? Criteria |
|
Definition
Look for duplicated regions in yeast genome.
Criteria: 1)Strong sequence similarity,2)At least 3 genes per region,3)Gene order is conserved |
|
|
Term
| Is yeast an ancient tetraploid? Result |
|
Definition
|
|
Term
| Is yeast an ancient tetraploid? Explanation |
|
Definition
1)Each region duplicated separate
2)There was one complete genome duplication, followed by gene loss and chromosome rearrangement. |
|
|
Term
| 2R hypothesis:observation, prediction |
|
Definition
Hox genes = a group of genes arranged in order,involved in the body plan during development. Tere is 1 cluster of Hox in fly, 4 clusters in human.
Predictions of 2R hypothesis:
1)Many gene clusters should be found in 4 copies 2)Phylogenetic relationship should be “2 x 2” |
|
|
Term
|
Definition
increase in chromosome number, but not by
an integral of the typical haploid set. |
|
|
Term
| Polysomy:definition, relation to evolution,explanation |
|
Definition
| duplication of 1 complete chromosome,is almost always deleterious,not thought to play a major role in evolution,this is probably due to an imbalance in gene expression |
|
|
Term
|
Definition
| pairs of genes (protein-encoding) in same genome with BLAST score 10^-10 |
|
|
Term
| Estimation of age of duplicated,selection |
|
Definition
| The age can be estimated from the number of differences between the two gene copies at "silent” sites.There is little or no selection on silent sites, so they change at a constant rate. |
|
|
Term
| Fates of duplicated genes |
|
Definition
a) Degeneration into pseudogene
b) Maintenance of two redundant genes
c) Adoption of new function (neofunctionalization)
d) Subfunctionalization |
|
|
Term
| Maintenance of two redundant genes |
|
Definition
| May be a short-term adaptation to increase gene activity (expression), but is unlikely to be maintained over long |
|
|
Term
| Neofunctionization,examples |
|
Definition
One copy gains a new function by chance.If the new function is advantageous, the new gene will be favoured.Sdic=Sperm-specific
Dynein Intermediate Chain,duplication of the Cdic gene (Cytoplasmic Dynein Intermediate
Chain). Janus-Ocnus |
|
|
Term
|
Definition
| if the original gene has two different functions, then after duplication each copy may lose one of the functions by mutation. Both copies must be maintained. |
|
|
Term
| Does duplication makes gene less esential? |
|
Definition
| knock-out of a single copy gene is more likely to have a major effect on phenotype than the knock-out of a gene with close paralog in genome. Phenotypic masking between paralogs is rare. Non-essential genes are more likely to undergo duplication. |
|
|
