02227naa a2200253 a 450000100080000000500110000800800410001910000230006024500950008326000090017830000120018752013280019965000290152765000170155665000180157365000220159165300110161365300220162465300260164670000160167270000190168870000210170777302450172818043572017-03-31       2000    bl ---       0--  u    #d1 aABREU, U. G. P. de  aFactors which influence weight and reproduction parameters in pantaneiro cattle in Brazil.  c2000  a(P-06).  aNatural selection is a result of differential, and not causal, reproductive rates of different genotypes. This causes the differential perpetuation of alleles and gene complexes and, as a result; those genotypes that are more resistant produce a greater number of viable and fertile descendents. The Pantaneiro cattle originated from animals imported from the Iberian penninsula which ended up in the Pantanal region during the colonization process during the XVII, XVIII and XIX centuries. At the beginning of the XX century, these highly adapted breeds began to be cross with the newly arrived zebu type cattle from India, especially the Nellore breed. Therefore, the principal source of genic and genotype changes in the Pantaneiro cattle was natural selection for over 300 years. Protein polymorphism is an important technique in the characterization and management of populations, allowing estimates of diversity, similarity and genetic distances. Another possibility is the association between genetic markers and economically important traits, thereby accelerating selection. The present work analyses the effects of various which influence productive and reproductive characters of the Pantaneiro cattle nucleus in EMBRAPA Pantanal, including relationships between protein polymorphisms and these productive traits.  aanimal genetic resources  aPolimorfismo  aProdutividade  aRecurso Genético  aBovine  aBovino pantaneiro  aProtein polymorphisms1 aMcMANUS, C.1 aLARA, M. A. C.1 aSERENO, J. R. B.  tIn: GLOBAL CONFERENCE ON CONSERVATION OF DOMESTIC ANIMAL GENETIC RESOURCES, 5., 2000, Brasilia. Proceedings... Brasilia: Embrapa Genetic Resources and Biotechnology, 2000. CD-ROM. (Embrapa Genetic Resources and Biotechnology. Document, 49).