Identification of microsatellites in cattle unigenes

To identify EST-SSR molecular markers, 41,986 cattle UniGene sequences from NCBI were mined for analyzing SSRs. A total of 1,831 SSRs were identified from 1,666 ESTs, which represented an average density of 19.88 kb per SSR. The frequency of EST-SSRs was 4.0%. The dinucleotide repeat motif was the most abundant SSR, accounting for 54%, followed by 22%, 13%, 7% and 4%, respectively, for tri-, hexa-, penta- and tetra-nucleotide repeats. Depending upon the length of the repeat unit, the length of microsatellites varied from 14 to 86 bp. Among the di- and tri-nucleotide repeats, AC/TG （57%） and AGC （12%） were the most abundant type. Annotation of EST-SSRs was also carried out. Three hundred primer pairs were randomly designed using Prime Premier 5.0 program and Oligo 5.0 for further experimental validation.

Assessment of Serum PRL,MLT,TSH,FSH and LH Concentrations in the Goat (Capra hircus) Exposing to Different Photoperiod Regimes

In many seasonally breeding species, photoperiod is an important factor involved in reproduction. Capra hircus breeds are normally considered short-day breeders. An experiment was carried out to evaluate whether or not photoperiodic regimens influence circulating hormone levels （prolactin, melatonin, thyrotropin stimulating hormine, luteinizing hormone,follicle stimulating hormone） of Henan huai local goat exposing to different photoperiodic regimens. The results showed that plasma levels of prolactin, melatonin, thyrotropin stimulating hormine, luteinizing hormone and follicle stimulating hormone were higher in the 8 L∶ 16 D photoperiodic regimen than that in the 16 L∶ 8 D photoperiodic regimen. Levels of those hormones decreased on day 7 and day 28 when the 16 L∶ 8 D photoperiodic regimen was used continuously. It was concluded that serum concentrations of the hormones increased in summer when short day （8 L∶ 16 D） was used and decreased when the goats were transferred from short day for 42 d to long day exposure for 28 d. We suggest that in summer, levels of hormones changing may be due to short day animals. Changing of related hormones is still determined by the mechanism of internal regulation of short day animal s exposure to light changes. Shortening light may also help increase the reproductive activity of goat and thus increase productivity.

Characteristics of genetic basis copy number variation in production and adaptation traits of Chinese indigenous sheep

Copy number variations(CNVs)range in size from 50 base pairs(bp)to several megabases(Mb)and encompass various types of structural variations,such as insertions,deletions,duplications,and complex multiallelic events(MacDonald et al.,2014).These genomic alterations modulate phenotype by altering gene dosage and transcriptional regulation,and are key drivers of biological evolution and determinants of genetic diversity and phenotypic variation.In recent years,CNVs have been detected in the genomes of various livestock species(Yuan et al.,2021;Chen et al.,2022).Upadhyay et al.(2017)conducted a comprehensive analysis of CNV distribution in the European cattle genome and determined that the Kit gene is associated with color-sidedness in English longhorn cattle.Another study presented extensive genome-wide information on CNVs in wild,commercial,and local chicken breeds to gain an integrated understanding of the domestication process and exclusively identified the genes involved(Chen et al.,2022).