The Cayapa Indians of Ecuador: A Genetically Isolated Group With Unexpected Complement C7 M/N Allele Frequencies

Abstract

The Cayapa Indians live in north-western Ecuador in close proximity to a Black population of African ancestry. C7 M/N allotyping has proved to be a good technique for plasma genetic analysis in several populations. Investigation of 124 Cayapa plasma samples revealed the highest allele frequency of C7*N observed in any population examined so far (0.36 versus 0.225 or lower). The marked difference in frequency compared with several Oriental populations, which are believed to have been derived from the same Asian population as native Amerindians, may reflect the effect of a small founder population followed by a high degree of genetic isolation. The allele frequency of 0.12 for C7*N determined for the neighbouring Black population supports the conclusion that there has been a lack of genetic admixture of Cayapas with other populations, confirming the results of ethnohistorical investigations and other protein polymorphism studies.

Genetic response to an environmental pathogenic agent: HLA‐DQ and onchocerciasis in northwestern Ecuador

“…Differences in the clinical presentation of the disease have been described between African and American populations (12). In the Ecuadorian focus of Esmeraldas, in the northwestern rainforest, the native Cayapas and the Afro‐Ecuadorians, whose origin traces back to the 17th century transatlantic slave trade, live very close to each other, yet there is very little intermarriage between them (13–16). Both populations are coresidential in a marginal tropical forest area known to be hyperendemic for onchocerciasis (17–19): several studies have verified that the prevalence of infection among the indigenous population and Afro‐Ecuadorians is virtually identical.…”

Reference Typing Report for Complement Components C6, C7 and C9 Including Mutations Leading to Deficiencies

“…Thus, the pattern shows a complete band-interval shift towards the cathode which can only be seen when run beside C7 1 samples. and 0.95, respectively) or for Ecuadorian Cayapa Indians (0.64) as reviewed [45].…”