Diversos processos fisiol?gicos e metab?licos t?m a participa??o do fator de crescimento semelhante ? insulina 1 (IGF-1). Durante os processos de crescimento mam?rio e gravidez, este fator atua na a??o local de horm?nios ester?ides, do horm?nio do crescimento e da prolactina, os principais reguladores da diferencia??o. Al?m disso, ? um fator necess?rio para o desenvolvimento do l?bulo-alveolar da gl?ndula mam?ria. O NF1-C2 ? o gene que codifica o fator de transcri??o nuclear 1-C2, o qual media a a??o da prolactina na gl?ndula mam?ria e desempenha um papel importante na ativa??o de v?rios genes espec?ficos desta gl?ndula, participando tanto do seu estabelecimento como na prote??o contra tumores durante a prolifera??o. Sendo assim, objetivamos com o presente estudo avaliar se as varia??es encontradas nos genes IGF-1 e NF1-C2 de caprinos das ra?as Xinjiang e Nanjiang cashmere (IGF-1) e Xinong Saanen Guanzhong Xinjiang cashmere branca (NF1-C2) est?o presentes em uma popula??o experimental de caprinos das ra?as Saanen e Alpina, relacionando-as com a produ??o de leite, dura??o da lacta??o, contagem de c?lulas som?ticas e teor de constituintes do leite (prote?na, gordura, lactose e extrato seco total), e detectar marcadores moleculares que possam ser utilizados na sele??o e melhoramento animal. Foi utilizado um rebanho de cabras (Capra hircus), em idade reprodutiva, composto por animais das ra?as Saanen e Alpina, sendo considerada uma ?nica popula??o, genotipadas para os polimorfismos dos genes IGF-1 e NF1-C2. O sangue coletado da circula??o perif?rica (aproximadamente 10 mL) foi utilizado para a extra??o de DNA gen?mico atrav?s das c?lulas sangu?neas brancas e a amplifica??o dos fragmentos foi feita por interm?dio da rea??o em cadeia da polimerase (PCR). Os fragmentos amplificados foram avaliados pelo polimorfismo no tamanho do fragmento de restri??o (PCR-RFLP), identificados por interm?dio de eletroforese em gel de poliacrilamida 5%, corado com nitrato de prata. Os produtos de PCR apresentaram tamanho aproximado conforme esperado, 363 pb (IGF-1) e 233 pb (NF1-C2), com um total de 168 e 197 animais avaliados, respectivamente. No ?ntron 4 do gene IGF-1 o polimorfismo de base ?nica (SNP) referente a transvers?o G>C na posi??o 5752 foi identificado por meio da endonuclease HaeIII, por?m o alelo A teve uma frequ?ncia muita baixa (0,09), e n?o houve associa??o significativa com nenhuma das caracter?sticas produtivas avaliadas (P>0,05). Logo, seu uso como marcador para estas caracter?sticas n?o ? recomendado. No gene NF1-C2, o SNP localizado no ?xon 5 (G>A), na posi??o 44654 da sequ?ncia de nucleot?deos, foi identificado atrav?s do uso da enzima de restri??o BstNI, os alelos A e G tiveram as frequ?ncias de 0,43 e 0,57, respectivamente. Foi encontrada associa??o deste polimorfismo com a porcentagem de prote?na do leite (P<0,01), com o gen?tipo AA associado ao maior teor do que o GG, enquanto o gen?tipo heterozigoto n?o diferiu dos homozigotos. Assim, este polimorfismo pode auxiliar na sele??o de animais que produzam um leite com maior conte?do proteico.

Several physiological and metabolic processes have the participation of the growth factor insulin-like 1 (IGF-1). During the breast enlargement process and pregnancy, this factor works in the local action of steroid hormones, growth hormone and prolactin, the primary regulators of differentiation. Besides is required for the development of mammary gland lobuloalveolar. The NF1-C2 is the gene encoding the nuclear transcription factor 1-C2, which mediates the action of prolactin in the mammary gland and plays an important role in the activation of several specific genes of this gland, participating both from its establishment as protect against tumors during proliferation. Therefore, we aim with this study: evaluate the variations found in IGF-1 and NF1-C2 genes in breeds of dairy goats cashmere Xinjiang and Nanjiang (IGF-1) and white cashmere Xinong Saanen Guanzhong Xinjiang (NF1-C2) are present in an experimental population of goats of Saanen and Alpine, relating them to milk production , lactation period, somatic cell count and milk constituents content (fat, protein, lactose, and total solids) and detect molecular markers that may be used in animal breeding and selection. A herd of goats (Capra hircus) in reproductive age, composed of animals of Saanen and Alpine breeds, considered as a single population, genotyped for polymorphisms of IGF-1 and NF1-C2 genes was used. The collected blood of peripheral circulation (approximately 10 mL) was used for genomic DNA extraction through the white blood cells and the amplification of the fragments was carried out by polymerase chain reaction (PCR). The amplified fragments were assessed for polymorphism by restriction fragment length (PCR-RFLP), identified via polyacrylamide gel electrophoresis 5%, stained with silver nitrate. PCR products showed approximate size as expected, 363 bp (IGF-1) and 233 bp (NF1-C2), with a total of 168 and 197 evaluated animals, respectively. In intron 4 of IGF-1, the single base polymorphism gene (SNP) refers to transversion G>C in position 5752 was identified by HaeIII endonuclease, but allele A had a very low frequency (0.09) and there was no significant association with neither of the productive characteristics (P>0.05). Therefore, its use as a marker for these traits is not recommended. In NF1-C2 gene, the SNP located in exon 5 (G>A), in position 44654 of the nucleotide sequence, was identified by BstNI restriction enzyme and frequencies of A and G alleles are 0.43 and 0.57, respectively. It was found association of this polymorphism with the percentage of milk protein (P <0.01), with AA genotype associated to greater content of protein than GG, while the heterozygous genotype did not differ from homozygotes. Therefore, this polymorphism may help select animals that produce milk with higher protein content.

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