ABSTRACT. The aim of current study was to survey genetic variability of PALM gene’s exon 3 and 4 by PCR-SSCP and DNA sequencing in Zel and Lori Bakhtiari sheep breeds. The SIFT (Sorting Intolerant from Tolerant) and PHyre2 program were used to predict the possible impact of amino acid substitutions on performance and structure of the paralemmin protein. A total of 140 animal's from 2 Iranian sheep breeds with different fat metabolisms, Lori-Bakhtiari and Zel sheep breeds were considered. The results showed that there are two polymorphic sites including a nonsynonymous substitution and an insertion mutation (49bp). Non-synonymous mutation deduced Thr20Ala amino acid exchange and ensuing two different structures for paralemmin protein that could be potentially affect protein structure and function during the interaction with glutamate in the cytosolic surface of plasma membrane. PALM gene, according to evolutionary path, is classified into two separate categories. In first covey, Gallus gallus and in second one, other species in several branches, so that the sequence of cow and sheep is placed in a sub-branch which forms a clade beside goat. Comparison of illustrated coding region sequences, PALM gene among different species, is of orthologous which are derived from a common ancestor.

ABSTRACT The objective of this study was to analyze the effect of environmental factors on egg production curve traits in broiler breeders. The weekly egg production records of birds collected from four different flocks were used to estimate the egg production curve parameters using the Compartmental function (y = A(1 − exp−b(t − d))exp−ct). The coefficient of determination (R2) obtained by the model was 0.98. Least squares analysis of variance indicated that the environmental factors such as hatchability and flock had significant effects on egg production curve traits. The highest correlation was observed between the weekly potential maximum yield and yield at the beginning of laying, whereas the lowest correlation was found between the weekly potential maximum production and production after peak yield. Associated factors with the increasing slope of egg production curves had a negative correlation with the decrease after peak. The correlation analysis showed that peak production had a negative and significant relationship with production towards peak and time to reach peak production, while there was a positive and significant correlation with the slope decrease after peak yield. The Compartmental function can be used as an alternative model to predict egg production traits in broiler breeders.