Term | Definition |
gene | segment of a chromosome that contains gentic code |
genome | entire set of human chromosomes |
autosomes | twenty-two pairs of chromosomes |
sex chromosomes | the 23rd pair of chromosomes |
dominant genes | have effects that appear in the offspring |
recessive genes | have effects that do not appear in offspring-masked by dominant gene |
genetic carrier | person who carries a recessive gene |
X chromosome | "female chromosome" |
Y chromosome | "male chromosome" |
genetic mutations | result in abnormalities in genetic code that cause disease |
single-gene disease | disease caused by individual mutant gene or groups of genes |
chromosomal diseases | diseases resulting from chromosome breakage or nondisjunction |
trisomy | a chromosome triplet |
monosomy | a single chromosome |
cystic fibrosis | single-gene disease characterized by excessive secretion of mucous and sweat |
phenylketonuria | (PKU)-single-gene disease characterized by excessive phenylketone in urine |
Tay-Sachs disease | (TSD)-single-gene recessive condition involving failure to make essential lipid enzyme |
Down syndrome | chromosomal disease caused by trisomy of chromosome 21 |
Klinefelter syndrome | chromosomal disease caused by presence of two or more X chromosomes in males (trisomy XXY) |
Turner syndrome | chromosomal disease-caused by monosomy of X chromosome |
pedigree | chart illustrating genetic relationships over several generations |
Punnett square | grid used to determine the probability of inheriting genetic traits |
karotype | arrangement of chromosome photographs used to detect abnormalities |
amniocentesis | karotype-collection of fetal cells floating in amniotic fluid |
chorionic villus sampling | karotype-involves collection of embryonic cells from outside chorionic tissue |