RESUMO
Recent studies of human populations suggest that the genome consists of chromosome segments that are ancestrally conserved ('haplotype blocks'; refs. 1-3) and have discrete boundaries defined by recombination hot spots. Using publicly available genetic markers, we have constructed a first-generation haplotype map of chromosome 19. As expected for this marker density, approximately one-third of the chromosome is encompassed within haplotype blocks. Evolutionary modeling of the data indicates that recombination hot spots are not required to explain most of the observed blocks, providing that marker ascertainment and the observed marker spacing are considered. In contrast, several long blocks are inconsistent with our evolutionary models, and different mechanisms could explain their origins.
Assuntos
Cromossomos Humanos Par 19/genética , Haplótipos/genética , Recombinação Genética , Alelos , Mapeamento Cromossômico , DNA/genética , Evolução Molecular , Frequência do Gene , Marcadores Genéticos , Humanos , Desequilíbrio de Ligação , Modelos Genéticos , Polimorfismo de Nucleotídeo ÚnicoRESUMO
This study examined the applicability of the 10% rule and the possible effect of years of work experience on the percent difference in grip strength for a sample of 124 factory workers in Indiana. The overall mean percent difference in grip strength, measured by the Jamar dynamometer, for both right- and left-handed participants was 6.3079%. A statistical difference was found (P = 0.029) in percent difference in grip strength among subjects with varying years of work experience. A significant difference (P = 0.007) also existed when comparing the right-handed scores to the left-handed scores of the Edinburgh Inventory. Results suggest that establishing grip strength norms for factory workers should not be determined by a percent difference rule, and the years of work experience need to be taken into consideration.
RESUMO
We have recently identified an autosomal recessive mutation in the Norway rat that generates an almost complete absence of normal hair. Here we describe a multilocus backcross analysis that was used to map this mutation, named shorn (gene symbol shn), to the distal end of rat chromosome 7. Although this region in rat carries no previously mapped similar mutations, the homologous genomic regions in mouse and human contain several potential homologues and candidate genes.