Acquired: occurring at a later time point; malignant conditions.
polyploid: whole set of chrom. (triploid 3n, tetraploid 4n)
aneuploid: in individual chrom. (trisomic 2n+1, monosomic 2n-1)
reciprocal translocation – translocation resulting from breaks on two different hromosomes and a subsequent exchange of material. Carriers of reciprocal translocations maintain the normal number of chromosomes and normal amount of chromosome material.
robertsonian translocation – translocation in which the long arms of two acrocentric chromosomes are fused at the centromere; the short arms of each chromosome are lost. The translocation carrier has 45 chromosomes instead of 46 but is phenotypically normal because the short arms contain no essential genetic material.
Deletion – loss of chromosome material. Opposite of duplication (see below).
Ring – ends of chrom. Lost and the new ends fuse together.
Inversion – two breaks occur, followed by reinsertion of the chromosome segment, but in reversed order.
Paracentric– inversion that does not include centromere.
Pericentric – inversion that includes the centromere.
Duplication – presence of an extra copy of chromosome material.
polyspermy – fertilization of egg by 2 sperm (2/3)
fertilization between normal haploid and a diploid gamete (1/3)
characterization: fusion of fingers, large placenta; most lost by birth.