in order to identify the segre qtl affecting growth traits on the end region of chromosome 18 in a lori-bakhtiari sheep population, 162 animals from 5 paternal half-sib families were taken to be studied. phenotypic data included records of birth weight (bwt), weight at one month of age (w1), weaning weight (wwt), weight at six months of age (w6), chest circumference (gi6), body length (lg6), wi...

When mammalian social groups exceed their optimal size, they often tend to split. In view of the potential evolutionary benefits, it should be more advantageous for animals to stay with kin, rather than nonkin, during such fission events. In the present study, the spontaneous fission of two social groups, R and S, of rhesus macaques living on Cayo Santiago, Puerto Rico, provided the opportunity...

the availability of the saturated dna marker maps in livestock has made it possible to locate quantitative trait loci (qtl) in these domestic animals. the objective of this research was to investigate the principles of applying the simple regression for qtl analysis in paternal half-sib (phs) design commonly used in livestock species. the theoretical aspects of the simple regression approach fo...

Forming strong, equitable, and enduring social bonds with a few individuals in a group carries adaptive benefits in terms of increased longevity, offspring survival and paternity success in birds and mammals, including humans. These recent insights generated a new interest in the factors creating variation in the strength of social relationships. Whether and how animals discriminate paternal ki...

The first-lactation milk records of 20,850 artificially sired Holstein cows and their darns were analyzed by a sire-by-herd, variance components model to determine if unequal numbers of records in the filled subclasses had any effect on the paternal half-sib correlatiou or the daughter-dam regression. The variance components were estimated with the number per subclass held constant at 1, 2, 3, ...

OBJECTIVES Genealogies contain information on the prevalence of different sibling types that result from past reproductive behavior. Full sibling sets stem from stable monogamy, paternal half siblings primarily indicate male reproductive skew, and maternal half siblings reflect unstable pair bonds. METHODS Full and half sibling types are calculated for a total of 61,181 siblings from publishe...

Hybrid vigor or heterosis results from the combination of genetically distant genomes at fertilization, and as well as being of major commercial importance, it is held to contribute significantly to fitness [1]. Activation of the paternal genome marks the transition from maternal to zygotic control of development, but a reported delay of paternal-genome activation in flowering plants [2-4] and ...

objective: to determine the effect of paternal age on preterm births in iranian neonates. materials and methods: from january 2005 to january 2006, two hundred eighty one preterm neonates born in mirza kuchakkhan hospital enrolled in this cross-sectional study. a structured questionnaire was applied for recording following data: birth weight, sex, gestational age, maternal age and paternal age....