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Muscle Depth (muscle + depth)
Selected AbstractsRadio transmitters do not affect the body condition of Savannah Sparrows during the fall premigratory periodJOURNAL OF FIELD ORNITHOLOGY, Issue 4 2009Lauren F. Rae ABSTRACT Radio telemetry can be a valuable tool for studying the behavior, physiology, and demography of birds. We tested the assumption that radio transmitters have no adverse effects on body condition in an island population of Savannah Sparrows (Passerculus sandwichensis). To assess possible changes in condition, 20 radiotagged and 25 nontagged Savannah Sparrows were captured and recaptured throughout the postfledging period. We used four measures of condition: mass, an index of fat free dry mass (measured via heavy water dilution), pectoral muscle depth (measured via ultrasound imaging), and an index of fat mass (measured via heavy water dilution). Using both a generalized linear modeling framework and paired design, we found no significant differences in the body condition of radiotagged and nontagged adults and juveniles. Thus, our results provide evidence that radiotransmitters have no effect on the condition of Savannah Sparrows during the premigratory period. RESUMEN La radiotelemetría puede ser una herramienta valiosa para estudiar la conducta, fisiología y demografía de aves. Utilizando una población de gorriones (Passerculus sandiwichensis), pusimos a prueba el postulado de que los radiotransmisores no tienen efecto adverso sobre la condición corporal de las aves. Para determinar el posible efecto en la condición de los pájaros, capturamos y recapturamos 20 individuos con radiotransmisores y 25 individuos sin estos, durante el periodo de post-volantones. En el trabajo utilizamos cuatro medidas de condición: masa, un índice de masa-seca sin grasa (medida a través de una dilución de agua pesada), profundidad de los músculos pectorales (determinado con una máquina de ultrasonido) y un índice de masa de lípidos (medida vía una dilución de agua pesada). Utilizando tanto un andamiaje con modelo linear generalizado y un diseño pareado, no encontramos diferencias significativas en la condición corporal entre los adultos y juveniles con o sin transmisores. Nuestros resultados proveen evidencia de que los radiotransmisores no tienen efecto adverso en la condición de los gorriones estudiados durante el periodo migratorio. [source] Two single nucleotide polymorphisms in the myostatin (GDF8) gene have significant association with muscle depth of commercial Charollais sheepANIMAL GENETICS, Issue 4 2008G. Hadjipavlou Summary To assess whether the same mutation(s) were responsible for similar phenotypes attributed to ovine chromosome 2 (OAR2) quantitative trait loci (QTL) in different sheep breeds, Suffolk, Texel and Charollais rams from British commercial flocks were genotyped for two single nucleotide polymorphisms (SNPs) located in the myostatin (GDF8) region of OAR2, previously detected in progeny of Belgian Texel rams exhibiting muscular hypertrophy. The first SNP (g.,2449G>C) was located upstream from the transcription start site and the second SNP (g.+6723G>A) in the 3, UTR of GDF8. The g.,2449C and g.+6723A alleles were absent in the Suffolk sires sampled, almost fixed in the Texel and segregating in the Charollais sires. Mixed model association analyses using SNP data on 338 Charollais lambs from 17 paternal half-sib families and phenotype and pedigree data on 56 500 lambs revealed that both SNPs had a significant association with muscle depth (P < 0.001). The SNPs were segregating at intermediate frequencies (p = 0.3) and exhibited strong linkage disequilibrium (r2 = 0.90). Animals with the g.+6723AA genotype had significantly greater muscle depth than those with either the g.+6723GG or the g.+6723AG genotypes (P < 0.002), with the g.+6723A allele, the likely causative mutation, having an additive effect of 1.20 (±0.30) mm and a dominance effect of ,0.73 (±0.36) mm. Based on estimated allelic effects and sample allele frequencies, the g.+6723G>A SNP explained 14% of the additive genetic variance of muscle depth. The maximum genetic variance for the trait (38%) attributed to the SNP would be attained at a g.+6723A allele frequency of 0.7. Our findings indicate that marker-assisted selection using these two GDF8 SNPs would be beneficial for the Charollais breed. [source] |