There is a site on one arm that has a demonstratable fixed break point. Insertion ins There must be two break points in one chromosome that allow a segment to insert between a break point in another chromosome. The arms of a chromosome are mirror images of each other. Monocentric isochromosomes have two long arms or two short arms. Dicentric isochromosomes have mirrored material between centromeres.
Marker mar A small extra piece of chromosomal material that travels with the other chromosomes.
Autosomal monosomies yield non-viable embryos. Only monosomy X is rarely liveborn. Ring r Breakage of a chromosome at two points is followed by repair with fusion to a circular chromosome. There is an exchange of material between arms on different chromosomes. Triploidy 69, Three haploid sets of chromosomes are present in a cell.