| A | B |
|---|
| chromosome theory of heredity | genes are located on chromosomes and each gene is at a specific place |
| linked gene | genes that are inherited together and do not undergo independent assortment |
| linkage groups | genes that are inherited in a group |
| recombinant | individuals with new combinations of genes due to crossing over |
| sex chromosomes | mismatched chromosomes that may differ in males and females; X and Y |
| autosomes | chromosomes which are the same in males and females |
| X chromosome | sex chromosome found in a pair in females |
| Y chromosome | sex chromosome found with an X in males |
| sex-linked | a gene located on one of the sex chromosomes; colorblindness is an example |
| mutation | mistakes in duplicating and transmitting genetic information |
| chromosomal mutation | change in the number or structures of chromosomes |
| nondisjunction | failure of homologous chromosomes to separate normally during meiosis |
| polyploidy | condition in which an organism has extra sets of chromosomes; fatal in animals |
| gene mutation | change involving the nucleotides of DNA |
| point mutation | gene mutations affecting only a single nucleotide |
| frameshift mutation | gene mutation that involves addition or deletion of a nucleotide that alters every codon after the mutation |
| incomplete dominance | active allele does not compensate for the inactive allele; white and red carnations are example |
| codominance | both alleles of a gene are expressed; cattle with mixed red and white hair are example |
| polygenic | traits controlled by two or more genes |
| operon | genes that work together + nearby regions that control them |
| operator | repressor binds here when operon is turned off |
| promoter | RNA polymerase binds here to start transcription |
| inducer | binds to the repressor and causes it to fall off operon |
| repressor | special protein that binds to the operator and turns off an operon |
| translocation | part of one chromosome breaks off and attaches to another nonhomologous chromosome |
| inversion | part of a chromosome "flip-flops" and reverses direction |
| deletion | loss of part of a chromosome |
| duplication | segment of a chromosome is repeated |
| Walter Sutton | author of the chromosomal theory of heredity as a young graduate student |
| Gregor Mendel | father of Genetics |
| Thomas Hunt Morgan | American scientist who was the first to describe linkage groups of chromosomes |
| Jocab and Monod | scientists who first described how genes are expressed in prokaryotes |
