The hypervariable 1 region of human mtDNA shows markedly reduced variability in Polynesians, and this variability decreases from western to eastern Polynesia. Fiftyfour sequences from New Zealand Maori show that the mitochondrial variability with just four haplotypes is the lowest of any sizeable human group studied and that the frequency of haplotypes is markedly skewed. The Maori sequences, combined with 268 published sequences from the Pacific, are consistent with a series of founder effects from small populations settling new island groups. The distributions of haplotypes were used to estimate the number of females in founding population of New Zealand Maori. The three-step simulation used a randomly selected founding population from eastern Polynesia, an expansionary phase in New Zealand, and finally the random selection of 54 haplotypes. The results are consistent with a founding population that includes Ϸ70 women (between 50 and 100), and sensitivity analysis shows that this conclusion is robust to small changes in haplotype frequencies. This size is too large for models postulating a very small founding population of ''castaways,'' but it is consistent with a general understanding of Maori oral history as well as the results of recent canoe voyages recreating early trans-oceanic voyages.

This article describes a multiplex allele-specific PCR (AS-PCR) approach for detection of an A to G mutation occurring in the human mitochondrial 12s RNA gene at nucleotide 1555. Possession of this mutation has been shown to be associated with irreversible hearing loss following administration of aminoglycoside antibiotics, and in some families is associated with profound sensorineural deafness in the absence of aminoglycoside antibiotics. We screened 206 unrelated individuals from the province of Otago, New Zealand, and found one who possessed the mitochondrial 1555 A to G mutation (0.48%; 95% confidence interval, 0.01-2.75).

A group of patients with prealbumin associated hyperthyroxinemia possess a common single base substitution in the fourth exon of their transthyretin gene. This cytosine to thymine substitution occurs in the codon for residue 119 and results in the predicted replacement of a threonine residue with a methionine at this position. A new NcoI restriction endonuclease cleavage site is created by the point mutation and can be detected by a rapid and simple assay based on the polymerase chain reaction. This variant transthyretin is inherited in an autosomal dominant manner and is apparently not amyloidogenic but is associated with increased thyroxine binding. As healthy heterozygous individuals have normal serum thyroxine concentrations, the hyperthyroxinemia sometimes found may not be primarily due to the variant.