The strange case of twins from different parents that amazes the world | the Chronicle

The National University of Colombia (UNAL), through its news agency, revealed last Tuesday a single case of twins from different parents. According to the UNAL website, the analysis began in 2018, when scientists received the alleged father’s request for a paternity test because he suspected his relationship with the children.

She was a doctor of science and biology from UNAL, Lilián Andrea Casas Vargas, who ensured that in this case they had to do a test called “Y chromosome panel”, since the twins were children.

In the analysis, the scientists’ goal was for the Y chromosome to be the same as the father’s, but after conducting the study “the genetic profile coinciding with one of the twins is again observed, while with the other, 14 of the 17 non-coincidences were identified, which corroborates the exclusion ”.

The geneticist assured that the test had to be repeated several times, but then the case had to be confirmed, which, due to its rarity, was published in the Biomedical Journal of the National Institute of Health.

“In Colombia, heteropaternal superfertilization –As the case of twins of different parents is known in a specialized manner– is an extremely rare phenomenon which occurs when a second egg, released during the same menstrual cycle, is fertilized by sperm from a different man in a separate sex“, explains the scientific publication.

“I don’t know if other labs have found cases like thisDr Casas said.

The team of geneticists who signed the article is completed by Fernanda Mogollón, Fredy Rodriguez Yes William Usaquén.

The latter reported that around 11,000 paternity tests are carried out each year in Colombia. “Although it is a simple procedure, this test is very emotionally charged due to the type of social and cultural implications it has. The parentage opinions reveal a series of prejudices still latent in Colombian society against issues such as motherhood or sexuality “Usaquén concludes.

Other cases of heteropaternal overfertilization

Heteropaternal superfertilization is rare in humans, but common in dogs, cats and cows, among which the exchange of sexual partners in a short period of time is much more frequent.

Two scientific studies from the early 1990s, cited by The Guardian, provide different figures on the frequency of these cases. They are placed in 1 in 400 fraternal twins. Another maintains that it is one at 1:00 p.m.0. But there are few studies on the subject, and cases are revealed only when there are doubts about paternity and the parents decide to do a genetic analysis.

Only two cases have been discovered in recent years. One in China and one in the United States and both were discovered due to doubts about the authorship of those involved.