English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

In order to investigate the origin(s) of the mutation(s) leading to the beta S-globin gene in North American populations of African ancestry, we analyzed DNA polymorphisms in the beta-globin gene cluster in a large number of both beta A- and beta S-globin gene-bearing chromosomes in U.S. and Jamaican Blacks. We found 16 different haplotypes of polymorphic sites associated with 170 beta S-globin gene-bearing chromosomes. The three most common beta S haplotypes, which account for 151/170 of the beta S-globin gene-bearing chromosomes, are only rarely seen in the chromosomes bearing the beta A-globin gene in these populations (6/47). Two observations suggest multiple origins or interallelic gene conversion, or both, of the beta S mutation. First, the mutation is present in all three beta-globin gene frameworks. Second, the beta S haplotypes can be divided into four groups, each of which cannot be derived from any other by less than two crossing-over events. In summary, our observation of the beta S mutation on 16 different haplotypes in African populations can be best explained by (i) a number of simple recombination events 5' to the beta-globin gene and (ii) up to four independent mutations and/or interallelic gene conversions.

Origin of the beta S-globin gene in blacks: the contribution of recurrent mutation or gene conversion or both.