Genes are mostly located in chromosomes but also in mitochondria, chloroplasts and plasmids
Chromosomes are found in the nucleus of a eukaryote and in the cytosol a prokaryote.
- extra chromosomes but not a set
- eg., trisomy 2N +1, monosomy 2N-1
- trisomy 21: 2N +1 (Down’s Syndrome)
- Klinefelter syndrome XXY (extra X chromosome)
- may result from non disjunction in meiosis at anaphase 1 or 2 (i.e both chromosome go to one cell and don’t split into 1 in each cell.
- extra sets -polyploidy
- eg., triploid (3N), tetraploid (4N)
- triploid bananas, tetraploid grapes (extra chromosomes in cells so fruit is bigger)
- Triploidy in humans is not compatible with life