Genetic studies on the Ticuna, an eniǵmatic tribe of Central Amazonas

Abstract

The Ticuna are an Amerindian tribe of Central Amazonas, a key location in theories of the peopling of eastern South America. The results of typing some 1760 members of the tribe with respect to 37 different genetic systems are reported, as are the results of HLA typings on a subsample of 129 persons. Salient findings include the following. (1) Except for a high frequency of LMs allele and an unusual combination of HLA allele frequencies, there are no notable findings with respect to the commonly studied polymorphic systems. A multivariate treatment of six of the most commonly studied genetic polymorphisms accords the Ticuna an 'average' position among Amerindian tribes. (2) There is much less intervillage heterogenicity than usually encountered in Amerindian tribes; this is attributed to recent high rates of intervillage migration due to religious developments. (3) A thus-far unique polymorphism of ACP1 was identified, the responsible allele having a frequency of 0.111. (4) In proportion to the size of the tribe, there was a relative paucity of 'private' genetic variants, the ACP1 allele being the only one. This discrepancy is attributed to a relatively recent numerical expansion of the tribe; effective population size over the past several thousand years is thought to have been well below what present numbers would suggest. (5) The thesis is again advanced that 'private variants' (alleles not occurring as polymorphisms of wide distribution) are more common in Amerindian than in Caucasian or Japanese populations.

Ancestry informative markers in Amerindians from Brazilian Amazon

“…The allele FY-Null*2, which presents high frequencies within African populations (Parra et al, 1998), was observed only in one heterozygous individual from the Belém village. This supports the low admixture levels with nonindigenous previously reported by Neel et al (1980) based on classical markers.…”

“…We report here the frequencies of seven of these markers in four Amerindian tribes (Tikú na, Kashinawa, Baníwa, and Kanamarí) characterized by low admixture levels with nonindigenous people (estimated as 2-3% according to classical markers; Mohrenweiser et al, 1979;Neel et al, 1980). These frequencies differentiated each of the tribes from each other.…”

European ACP1*C Allele Has Recessive Deleterious Effects on Early Life Viability

“…ACP1 has four major codominant alleles that reach polymorphic frequencies, two with global distributions (ACP1*A and ACP1*B) and two with regional geographic distributions (ACP1*C and ACP1*R, which are restricted to Europe and sub-Saharan Africa, respectively). In addition, a number of minor alleles reach polymorphic frequencies in individual populations, such as ACP1*GUA among the Guaymi of Costa Rica and ACP1*TIC among the Ticuna of Brazil (Neel et al 1980;Barrantes et al 1982).ACP1 encodes two separate isozyme products through alternative splicing of the primary RNA transcript (Dissing and Sensabaugh 1987;Dissing et al 1991;Lazaruk et al 1993). Allele variants of ACP1 differ in their production of these isozymes with respect to both the total quantity and the ratio of isozymes produced [reviewed by Greene et al (2000)].…”

New studies on the Macushi Indians of northern Brazil

“…Some support for this viewpoint is found in tal~le 2. The Macushi gene frequencies as a whole do not depart markedly from those observed in other South American tribes and, indeed, are as close to the multivariate genetic mean for all tribes as any tribe we have studied thus far (see Neel et al 1980). On the other hand, as the appropriate studies continue to reveal rare tribal genetic variants, it may be possible that tribes will achieve individuality on this basis.…”