principle of genetic inheritance Flashcards
genes
segments of DNA in a chromosome
locus or loci (plural)
a gene’s location on a chromosome
chromatid
one of two identical copies of a chromosome
centromere
connects identical sister chromatids
telomere
region at the end of a chromosome, used for stability
somatic cells
all cells other than germ-line cells; diploid, 2 copies- one from each parent– 23 pairs of different chromosomes, (22 pairs of autosomes and one pair of sex chromosomes) 46 total– diploid
homologous chromosomes
pairs of chromosomes
polymorphisms
DNA sequence variants that are more common in populations; “many forms” describing multiple alleles at a locus — loci that contain multiple alleles are called polymorphic
autosomes
chromosomes common in both genders, one from each parent – 22 pairs
karyotype
the entire set of a persons chromosomes; 46 chromosomes (of a karyotype) are in each diploid cell of a patient ;
normal karyotype is written as: 46XY and 46XX
genotype
an individuals genetic constitution at a locus
phenotype
what is actually observed physically
germ-line mosaicism
occurs when all or part of a parent’s germ-line is affected by a disease-causing mutation, but the somatic cells are not– it elevates the recurrence risk for offspring of the mosaic parent
the parent carries the mutation in his/her germ-line, but does not express the disease because the mutation in absent in other cells of the body
from lecture: a condition in which cells from a patient have different genotypes (& karyotypes)
- down’s syndrome: some 46XX, some 47XX, +21
- Klinefelter syndrome: some 46XY, some 47XXY
- turner syndrome: some 46XX, some 46XO
lyonization
X-inactivation; the choice of which X chromosome to be inactivated is random
during which phase of the cell cycle are chromosomes duplicated?
Interphase (G1, S, G2)
