RESUMO
Genotype data from 14 microsatellite markers were used to assess the genetic diversity and differentiation of four guanaco populations from Argentine Patagonia. These animals were recently captured in the wild and maintained in semi-captivity for fibre production. Considerable genetic diversity in these populations was suggested by the finding of a total of 162 alleles, an average mean number of alleles per locus ranging from 6.50 to 8.19, and H(e) values ranging from 0.66 to 0.74. Assessment of population differentiation showed moderate but significant values of F(ST)=0.071 (P=0.000) and R(ST)=0.083 (P=0.000). An amova test showed that the genetic variation among populations was 5.6% while within populations it was 94.4%. A number of 6.6 migrants per generation may support these results. Unambiguous individual assignment to original populations was obtained for the Pilcaniyeu, Las Heras and La Esperanza populations. The erroneous assignment of 18.75% Rio Mayo individuals to the Las Heras population can be explained by the low genetic differentiation found between these two populations. Thirty-nine of 56 loci per population combinations were in Hardy--Weinberg disequilibrium because of guanaco heterozygote deficiency, which may be explained by population subdivision. The high level of genetic diversity of the guanacos analysed here indicates that the Patagonian guanaco constitutes an important genetic resource for conservation or economic utilization programmes.
Assuntos
Camelídeos Americanos/genética , Variação Genética , Genética Populacional , Análise de Variância , Animais , Argentina , Primers do DNA , Frequência do Gene , Genótipo , Repetições de Microssatélites/genéticaRESUMO
Sweat glands are present all over the skin, where sweat production varies from 4.98 to 73.36gm(-2)h(-1) of skin. Ambient temperatures between 20 and 33 degrees C are the main stimuli for activation of sweat glands, generating a heat loss ranging from 11.9 to 37% of standing basal metabolic rate. Respiratory water loss is not an important mechanism for heat dissipation. Water loss is controlled by postural changes in the guanaco.
