Fertilization and Early Embryonic Errors

Forensic implications of the presence of chimerism after hematopoietic stem cell transplantation

“…Another option is that the oocyte replicates its genetic material before being fertilized by one sperm, or that it retains a polar body, and then the lonely female genetic material replicates again. In this case, one of the cell lines of the chimeric zygote would only have maternal genetic material, which is known as digynic chimerism [3].…”

“…Embryos that have undergone abnormal fertilization can also be modified, in a process known as post-zygotic splitting. In this case, a chimeric embryo undergoes a series of cell divisions that form a mass with mixed genetic material that divides into two embryos [3].…”

“…However, as it will be shown later, sometimes individual identification is hindered in people who have cells with different DNA, who are known as "chimeras". A chimera is an individual who possesses cells from two or more genetically different origins [2,3,4,5], and when dealing with samples showing these characteristics it is easy to mistake them for DNA mixture evidence or cross-contamination.…”