We often hear there is no such thing as perfect — a tough pill to swallow for perfectionists and narcissists alike. A Berkeley professor, however, suggests the “perfect” human does exist and can be found on a small Caribbean island just over 2,000 miles from mainland U.S. Lior Pachter, a computational biologist working in genomics at the university, believes the perfect human, genetically speaking, is a Puerto Rican woman, due to her DNA ancestry that allows her to possess the ideal genotype.

This DNA research stemmed from Nobel Prize winner James Watson’s obsession to improve the perfect human. Watson sought to "improve" the "imperfect human" via human germline engineering. But according to Pachter’s account of his encounter with Watson, he heard him spew racist and misognistic comments.

"I remember him asking rhetorically, 'Who would want to adopt an Irish kid?' (followed by a tirade against the Irish that I later saw repeated in the news), and he made a point to disparage Rosalind Franklin, referring to her derogatorily as 'that woman,'" Pachter wrote on his blog.

So, the computational biologist undertook the thought experiment to actually find the perfect human. Through an SNP database — single nucleotide polymorphisms, the most common type of genetic variation among people — he created the perfect human in silico by setting the alleles at all SNPs so they are “good” and “add the perfect human” to a panel of genotyped individuals from various populations to perform PCA (principal component analysis) to reveal the location and population origin of the individual.

Pachter further explained, “an SNP entry includes fields for ‘magnitude’ (a subjective measure of significance on a scale of 0–10) and ‘repute’ (good or bad), and allele classifications for many diseases and medical conditions.” He added, “If the genotype of an individual is known at many SNPs, it is therefore possible to guess where they are from.” Pachter then unveiled the perfect human with genetic advantages actually lives in the U.S.

“The nearest neighbor to the “perfect human” is HG00737, a female who is Puerto Rican,” he wrote.

Women who reside in the U.S. but were born on the island have been shown to have a mixture of 50 percent European, 30 percent West African, and 20 percent Native American. The perfect human is believed to have existed, and it could’ve been Yuiza (Loiza), a Taina woman who became the only female Cacique (chief) of her tribe in Puerto Rico’s history. This suggests to collect all the “good” alleles it is necessary to be admixed, but this itself is not sufficient for perfection, according to Pachter.

"It makes sense that an individual homozygous for all 'good' alleles should be admixed. And that is exactly what Puerto Ricans are, but admixture itself is not sufficient for perfection."

Researchers like Dr. Gerome Breen of King’s College London, who has worked in Brazil, have delved into the possibility that being mixed race allows a person to have more genetic variation or diversity, which can protect them from various parasites and infectious diseases, physical advantages, and even advantages in coping with stress. In Brazil, a country in which 86 percent of the population is mixed-race, Breen has been able to look at the influence of genetic heritage on mixed and non-mixed people.

In a study published in BMC Psychiatry, Breen found people who live with the unrelenting violence and extreme poverty of the favelas or city slums experience the same levels of stress as those who live in the affluent suburbs. Interestingly, in Brazil, the affluent people are overwhelmingly of European ancestry, while favelas are primarily home to people of mixed race. He believes mixed-race people are more likely to have a good functioning copy of each gene from their mother and father, which means they are more likely to have healthy biological systems that allow them to cope with stress.

Some of our genes — about seven percent of them — vary between continental populations and along races. The map of the human genome shows that the DNA of human populations across the world is a continuum. Genes that are obviously different between races include those that allow each population to adapt to new latitudes, maximize their success in certain environments, and protect them from the diseases that people are exposed to.

Science speculates being mixed race may contain biological advantages due to the genetic variation or diversity. Offspring tend to produce unpredictable characteristics that are advantageous to the human population. Diverse genetic ancestry could be the gateway to attaining better health.

Source: Andreoli SB, Blay SL, Breen G et al. Violence and post-traumatic stress disorder in Sao Paulo and Rio de Janeiro, Brazil: the protocol for an epidemiological and genetic survey. BMC Psychiatry. 2009.