| A | B |
|---|
| circle | symbol for female |
| homozygous | two alleles are the same |
| parents | horizontal line between individuals |
| shaded circle or square | individual displays or has the studied trait |
| homologous chromosomes | paired chromosomes with genes for same traits in same order |
| roman numeral | identify generations |
| heterozygous | two alleles are different |
| horizontal row | represents generation, most recent at the bottom |
| autosomes | 22 homologous chromosomes in human cell |
| huntington's disease | rare, lethal, dominant genetic disorder; areas of brain breakdown |
| arabic number | identify individual |
| vertical line | connects parents to offspring |
| square | symbol for male |
| pedigree | graphic representation of genetic information |
| tay-sachs disease | recessive genetic disorder; build-up of lipids in CNS |
| multiple alleles | trait being controlled by more than two alleles |
| carrier | 1/2 shaded symbol; heterozygous |
| external environment | nutrition & temperature; can affect gene expression |
| incomplete dominance | inherited phenotype of heterozygous individual intermediate between two homozygous parents |
| polygenic inheritance | trait controlled by two or more genes; phenotype shows range of variability |
| cystic fibrosis | recessive genetic disorder; build up of mucus in lungs and digestive tract |
| sex-linked inheritance | traits controlled by genes on sex chromosomes |
| codominance | both homozygous alleles expressed equally |
| phenylketonuria | recessive genetic disorder; build up of amino acid phenylaline |
| internal environment | can affect gene expression; example hormones and gender |
