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PubMed1998

Molecular population genetics of the Arabidopsis CAULIFLOWER regulatory gene: nonneutral evolution and naturally occurring variation in floral homeotic function.

The evolution of interspecies differences in morphology requires sufficient within-species variation in developmental regulatory systems on which evolutionary forces can act. Molecular analyses of naturally occurring alleles of the Arabidopsis thaliana CAULIFLOWER locus reveal considerable intraspecific diversity at this floral homeotic gene, and the McDonald-Kreitman test suggests that this gene is evolving in a nonneutral fashion, with an excess of intraspecific replacement polymorphisms. The naturally occurring molecular variation within this floral regulatory gene is associated with functionally different alleles, which can be distinguished phenotypically by their differential ability to direct floral meristem development.

Arabidopsis↗
PubMedDate not supplied

The effect of religious, cultural and social identity on population genetic structure among Muslims in Pakistan.

Knowledge of historical demography and contemporary social stratification can be valuable in understanding disease patterns, including genetic disorders, especially in communities that have a high prevalence of endogamous and/or consanguineous marriages. This paper provides a background to the religious, historical and socio-cultural factors that have helped define the bounds of endogamy for Muslims in undivided India and more specifically since the creation of Pakistan. The preference for endogamous marriage is based on the clan-oriented nature of the society, which values and actively seeks similarities in social group identity based on several factors, including religious, sectarian, ethnic, and tribal/clan affiliation. Religious affiliation is itself multi-layered and includes religious considerations other than being Muslim, such as sectarian identity (e.g. Shia or Sunni, etc.) and religious orientation within the sect (Isnashari, Ismaili, Ahmedi, etc.). Both ethnic affiliation (e.g. Sindhi, Baloch, Punjabi, etc.) and membership of specific biraderis or zat/quoms are additional integral components of social identity. Within the bounds of endogamy defined by the above parameters, close consanguineous unions are preferential due to a congruence of key features of group- and individual-level background factors.

Consanguinity↗
PubMed2003

Molecular population genetics of the Arabidopsis CLAVATA2 region. The genomic scale of variation and selection in a selfing species.

The Arabidopsis thaliana CLAVATA2 (CLV2) gene encodes a leucine-rich repeat protein that regulates the development of the shoot meristem. The levels and patterns of nucleotide variation were assessed for CLV2 and 10 flanking genes that together span a 40-kb region of chromosome I. A total of 296 out of 7959 sequenced nucleotide sites were polymorphic. The mean levels of sequence diversity of the contiguous genes in this region are approximately twofold higher than those of other typical Arabidopsis nuclear loci. There is, however, wide variation in the levels and patterns of sequence variation among the 11 linked genes in this region, and adjacent genes appear to be subject to contrasting evolutionary forces. CLV2 has the highest levels of nucleotide variation in this region, a significant excess of intermediate frequency polymorphisms, and significant levels of intragenic linkage disequilibrium. Most alleles at CLV2 are found in one of three haplotype groups of moderate (>15%) frequency. These features suggest that CLV2 may harbor a balanced polymorphism.

Alleles↗
PubMed1984

Population genetics of C4 with the use of complementary DNA probes.

The C4 system is unusually variant both in the number of expressed genes and in the variety of those expressed. It is also closely linked to other two complement loci (C2 and Bf), which are structurally distinct but not linked to the two complement loci (C3 and C5) which are structurally similar. The C2, Bf, C4 segment lies within the MHC system, and their closeness to one another, and to the surrounding recognition loci (HLA-A, -B, -C, -DR) makes it difficult to attribute benefit or handicap, in relation to any disease, to any single locus by simple comparisons. The variation at the protein level, expressed by specificity, or charge, or size, or haemolytic activity, can now be supplemented by variation at restriction sites, or in the length of DNA between sites. The latter may be either causally or coincidentally related to the variant proteins. These data provide information on the evolutionary relations of the variants, both within the between species, and on the determinants related to inadequate or inappropriate defence against disease. They also provide evidence relevant to the sufficiency of the classical explanations of mutation, recombination and misalignment with recombination, and selection as explanations for what exists now.

Alleles↗
PubMed2006

Blind population genetics survey of tropical rainforest trees.

Rainforest tree species can be difficult to identify outside of their period of reproduction. Vascular tissues from Carapa spp. individuals were collected during a short field trip in French Guiana and analysed in the laboratory with nuclear and chloroplast markers. Using a Bayesian approach, > 90% of the samples could be assigned to one of two distinct clusters corresponding to previously described species, making it possible to estimate the genetic structure of each species and to identify cases of introgression. We argue that this blind procedure represents a first-choice rather than a fallback option whenever related taxa are investigated.

Bayes Theorem↗
PubMed1975

Phosphoglucomutase 3: formal and population genetics and observations on abnormal phenotypes.

514 healthy blood donors and 47 families with 122 offspring were studied for phosphoglucomutase 3 (PGM3) from leukocytes. There was a good agreement of allelic frequencies obtained compared to those reported previously in Caucasians. In addition, three individuals with abnormal phenotypes were observed: one was a patient with Hodgkin's disease, the other two were apparently healthy blood donors. In two cases, family members could be studied; none carried the abnormal type of the father. The possible background of these observations with respect to the attachment of the PGM3 locus to the immunogenetic linkage group--the major histocompatibility complex--on chromosome No. 6 in man is discussed.

Chromosome Mapping↗