Martínez-Cruzado 2001, and its limits

In 2001, Juan Carlos Martínez-Cruzado and colleagues at the University of Puerto Rico at Mayagüez published a mitochondrial DNA study in Human Biology. They screened two sets of samples for the restriction markers that define the four major Native American mtDNA haplogroups. An unbiased sample showed Native American mtDNA in 52.6 percent of the people examined. A second sample, taken from people who said they had a maternal ancestor with Native American traits, showed 69.6 percent. Among those Native American lineages, haplogroup A covered 56.0 percent and haplogroup C 35.6 percent. Haplogroup D was not found.

Those figures are maternal only. Mitochondrial DNA is inherited from the mother. The study says nothing about fathers, nothing about how a person names themselves, and nothing about who is or is not Taíno in civic life. It is not a tribal roll. It is not a count of a nation. It does not mean "the island is mostly Taíno." Print the limit in the same breath as the number: 52.6 percent in the unbiased set is a claim about maternal lineages in a research sample, not about identity cards or census boxes.

The article's own abstract still speaks of the Taíno culture as extinct while arguing that the maternal contribution is considerable. That sentence is a habit, not a finding genetics can support. Culture, language, and self-naming are not restriction sites. The people on this island kept living, marrying, and farming after colonial counts dropped the word indio. Genetics can show that many Puerto Ricans carry Native American mtDNA. It cannot declare a people missing, and it cannot enroll one.

Use the study for what it is: evidence that Native American maternal ancestry is common in Puerto Rico, structured in haplogroups A and C, with little signal of later mainland native immigration in that maternal line. Then stop. The next claim — that the Taíno people did not become extinct — is historical and civic. It does not rest on a 2001 percentage. Genetics can support a family story. It cannot enroll a nation or close one.

Sources: Martínez-Cruzado et al., Human Biology 73.4 (2001), Wayne State; PubMed 11512677. Freeze 2026-08-22.