1.
allele: a different form of a particular gene
2.
aneuploid: a somatic cell that does not contain a multiple of 23 chromosomes
3.
autosomal: abnormal gene
4.
base-pair substitution: mutation in which one base pair is replaced by another. Sometimes change the amino acid sequence
5.
carrier: an individual that has a diseased gene but is phenotypically normal
6.
deletion: caused by broken chromosomes and loss of DNA
7.
diploid: have both member of each chromosome pair. Normal is 23 pairs
8.
disjunction: the normal separation and migration of chromosomes during cell division
9.
dominant trait: an allele that is observable
10.
duplication: are a form of chromosomal abberation. Have less serious complications than deletions
11.
euploid: cells that have a multiple of the normal number of chromosomes
12.
expressivity: the extent of variation in phenotype associated with a particular genotype
13.
fragile sites: an area where it is more prone to develop breaks and gaps when cultured in a folate-deficient medium
14.
frame-shift substitution: a mutation that involves the insertion or deletion of one or more base pairs to the DNA molecule. Greatly alters the amino acid sequence
15.
gamete: sex cells (sperm and egg)
16.
gene: a segment of DNA that codes for specific gene products
17.
genotype: the genetic makeup of an organism
18.
germline mutation: a mechanism by which a child can inherit a genetic disease even though the parents do not express the disease. The mechanism is believed to involve a mutation during the embryonic development of the parent germ cell
19.
haploid: have only one member of each chromosome pair
20.
heterozygous: when two alleles of a certain gene on a pair of homologous chromosomes are not identical
21.
homozygous: when both alleles of a particular gene on a pair of homologous chromosomes are identical
22.
inversion: the occurrence of two breaks in a chromosome followed by the reinsertion of the missing fragment at its original site, but in an inverted order
23.
karyotype: during metaphase, the chromosomes make an ordered display according to their position and size
24.
monosomy: has only one copy of a given chromosome in a diploid cell
25.
mutagen: agents known to increase the frequency of mutations
26.
mutational hotspots: certain areas of chromosomes that have a particularly high mutation rate
27.
nondisjunction: an error in which homologous chromosomes or sister chromatids fail to separate normally during meiosis or mitosis
28.
penetrance: the percentage of individuals with a specific genotype who also express the expected phenotype
29.
phenotype: a visible observation, or tested
30.
polyploidy: when a euploid cell has more than the diploid number of chromosomes
31.
recessive trait: an allele that is hidden
32.
sex-linked: a trait normally found on the sex chromosomes
33.
silent substitution: a mutation in which a base pair is replaced by another, but does not change the amino acid sequence
34.
spontaneous mutation: mutation that occurs in absence of exposure to known mutagens
35.
translocation: the interchanging of genetic material between nonhomologous chromosomes
36.
trisomy: has three copies of one chromosome
37.
x-linked: a trait normally found on the x chromosome
