| A | B |
|---|
| Map Units | the distance within which recombination (due to crossover) occurs 1% of the time |
| Linkage Map | based on the incidence of crossover, this can be constructed |
| Linked genes | genes on the same chromosome are always inherited together (unless separated by crossover) |
| Sex-Linked traits | traits located on the X chromosome |
| Mutations | occurs randomly; any change in the genome |
| Gene mutation | types are point, frame shift, deletion/addition translocations |
| Chromosomal mutations | mutations due to nondisjunction, visible in a karotype |
| Hemophilia | sex-linked recessive mutation; caused by the absence of one or more protein clotting factors |
| Karotype | a procedure carried out to identify chromosomal abnormalities; analyzes shape, size, and number of chromosomes |
| Aneuploidy | a chromosomal mutation; any abnormal number of chromosomes; ex. Down's syndrome |
| Polyploidy | a chromosomal mutation; having extra complete sets of chromosomes; ex. 3n or 4n (common in plants) |
| Autosomes | chromosomes other than X and Y sex chromosomes |
| Nondisjunction | an error that sometimes occurs during meiosis in which homologous chromosomes fail to separate; results in chromosome mutations |
| Fragile X syndrome | named for the physical appearance of the X chromosome; the tip of which seems to "hang by a thread"; the most common form of mental retardation in the U.S.; caused by excessive number of tandem repeats within the chromosome |
| Genomic imprinting | the expression of certain traits varies depending on which parent contributed the gene |
