Genetic origins in a South American clefting population

Abstract

It has been proposed that susceptibility to clefting in South America is related to Amerindian ancestry, where clefting is present at a higher frequency than in the other admixed populations (Caucasian and African) that make up the diverse racial mix of current South Americans. To clarify the genetic origins and establish a method for genetic mapping, mitochondrial DNA variation and Y-chromosome markers were studied in a South American population affected with clefting. Two-hundred and seventeen subjects and matched controls were selected through the Latin-American Collaborative Study of Congenital Malformations (ECLAMC). The case group showed a higher frequency of Native American haplogroups and a lower frequency of African haplogroups (p < 0.00001). In addition, the case group showed a much higher frequency of the specific native American haplogroup D than the control group (p < 0.00001). For the Y-chromosome markers, the case group showed a lower frequency of the African-specific marker, YAP (p = 0.002), and a higher frequency of the Native American-specific marker, DYS199 (p < 0.00001). Even though differences were found in the frequencies of the markers studied, the contribution of each founder population was similar for both groups. Results suggest a strong Native American maternal contribution and a strong Caucasian (Spanish and Portuguese) paternal contribution to the population studied. The implications of this finding include the possibility of using admixture mapping approaches to this population.

ECLAMC: The Latin-American Collaborative Study of Congenital Malformations

“…Molecular studies performed by ECLAMC had already produced 7 of the 29 papers ECLAMC has published since 2000 [13, 14, 15, 16, 17, 18, 19]. This start had been possible due to the fruitful collaboration with the laboratories led by Dr. Maximilian Muenke (NIH) and Prof. Jeffrey Murray (University of Iowa, USA).…”

<em>TIMP2</em> gene polymorphism as a potential tool to infer Brazilian population origin

“…The ethnic distribution of residents in São Paulo is 71.8% Caucasian, 4.2% African descendants, 22.6% Mulattos (children of intermarriages between Caucasians and African descendants), and 1.5% Japanese and Amerindian. 17 According to Callegari-Jacques and Salzano, [19][20][21] However, the Japanese population has rather limited genetic diversity, according to data from the Japanese Millennium Genome Project. 22 Population-specific SNPs may have important applications in anthropologic studies, such as studies of population genetic origins.…”

Riesgo de anomalías congénitas en grupos étnicos de Sudamérica

“…Los estudios Etnia-Malformación fueron desarrollados durante muchas décadas, intentando identificar grupos étnicos con mayor riesgo de un defecto congénito específico (Castilla et al, 1980;Martínez-Frías, 1998;Vieira et al, 2002;Canfield et al, 2006), lo que ha permitido sugerir la existencia de genes de susceptibilidad involucrados en la etiopatogenia de las malformaciones congénitas. Algunos de estos genes fueron identificados más tarde por estudios de genética molecular.…”

“…En la frecuencia de labio leporino, fueron reportadas diferencias étnicas, siendo elevada en asiáticos y en indoamericanos (Vieira et al, 2002), intermedia en caucásicos y baja en ancestros africanos. En poblaciones de Estados Unidos, se reportó una disminución del riesgo de labio leporino en nacimientos donde uno o ambos padres fueron afrodescendientes, respecto de aquellos en que ambos padres fueron de origen europeo (Khoury et al, 1983;Croen et al, 1998;Yang et al, 2004).…”