RESUMEN
BACKGROUND: Matching for HLA genes located on chromosome 6 is required in hematopoietic stem cell transplantation to reduce the incidence of graft-versus-host disease. However, a considerable proportion of patients still suffer from it, obviously due to genetic differences outside the HLA gene region. DESIGN AND METHODS: We studied the similarity of almost 4,000 single nucleotide polymorphisms on chromosome 6 between patients receiving hematopoietic stem cell transplantation and their HLA-matched sibling donors. RESULTS: We observed that as a result of routine HLA matching the siblings in fact shared surprisingly long chromosomal fragments with similar single nucleotide polymorphism genotypes--from 11.65 Mb to 134.66 Mb. The number of genes mapped on these shared fragments varied from 402 to 1,302. Considering the whole chromosome 6, the HLA-matched siblings were apparently identical for 65.2-97.8% of the single nucleotide polymorphisms. CONCLUSIONS: Potentially, genes similar in some transplantation pairs while different in others might have a significant role in determining the outcome after hematopoietic stem cell transplantation.
Asunto(s)
Cromosomas Humanos Par 6/genética , Trasplante de Células Madre Hematopoyéticas/métodos , Histocompatibilidad/genética , Antígenos HLA/genética , Prueba de Histocompatibilidad/métodos , Humanos , Polimorfismo de Nucleótido Simple , Hermanos , Donantes de TejidosRESUMEN
Birds need to acquire carotenoids for their feather pigmentation from their diet, which means that their plumage color may change as a consequence of human impact on their environment. For example, the carotenoid-based plumage coloration of Great tit, Parus major, nestlings is associated with the degree of environmental pollution. Breast feathers of birds in territories exposed to heavy metals are less yellow than those in unpolluted environments. Here we tested two hypotheses that could explain the observed pattern: (I) deficiency of carotenoids in diet, and (II) pollution-related changes in transfer of carotenoids to feathers. We manipulated dietary carotenoid levels of nestlings and measured the responses in plumage color and tissue concentrations. Our carotenoid supplementation produced the same response in tissue carotenoid concentrations and plumage color in polluted and unpolluted environments. Variation in heavy metal levels did not explain the variation in tissue (yolk, plasma, and feathers) carotenoid concentrations and was not related to plumage coloration. Instead, the variation in plumage yellowness was associated with the availability of carotenoid-rich caterpillars in territories. Our results support the hypothesis that the primary reason for pollution-related variation in plumage color is carotenoid deficiency in the diet.