Each homologous chromosome
contains the same set of genes in the same locations along the chromosome, though they may appear in differing alleles, which can affect the passing of genetic traits.
In these mutant cases, we assume that the force between sister chromatids or between homologous chromosomes
does not decrease, whereas this force is expected to decrease when a normal cell goes into anaphase of mitosis or meiosis I.
In pre-reductional meiosis, which is the more common type, homologous chromosomes
segregate in the first round of meiosis, and sister chromatids segregate in the second.
5q32 1 14q31 1 2q21 * 6q22 1 15q12 1 9q12 * 6q24 2 16q14 1 10q14 * 8q22 1 18q12 1 8q24 1 19q14 1 9q12 3 Xq17 1 9q22 1 Xq22 1 10q12 2 Xq24 1 10q14 4 Bold Italics indicate homologous chromosomes
In the process of biological evolution, two homologous chromosomes
are intermixed to generate newer chromosome patterns that produce new individuals or species.
Although many types of aberrations are found, the more commonly observed are deletion (loss of a small segment of a chromosome usually in only one homologue) leading to loss of information, translocation (a segment of one of the two homologous chromosomes
breaks and binds to the other), duplication (occurrence of the same sectors twice on the same chromosome), inversion (a particular sector is reversed in the chromosome), insertion (a new sector is inserted into the chromosome) and substitution (a certain chromosome sector is replaced with another).
The noise appears to be related either (1) to inconsistency in the quality of repetitive sequence-enriched DNA required for assay specificity or (2) to copy-number polymorphisms that are found in homologous chromosomes
from the same and from different individuals.
Complete TFPI deficiency in mice is lethal in the embryo stage of development, whereas heterozygosity (having two genes at corresponding alleles on homologous chromosomes
different for one or more alleles) is compatible with normal survival.