Haplotype association of ovine leptin gene on breeding value of body measurements in Makooei sheep breed

The research was undertaken to find association of genetic variation in the exon 3 of the leptin gene and breeding value of body weight traits in Makooei sheep breed using single strand conformation polymorphism (SSCP). The PCR product was obtained to encompass exon 3 of leptin gene corresponding to ovine leptin gene. The PCR fragments were subjected to electrophoresis to reveal the SSCP patterns. Among the total of 130 sheep, five SSCP patterns (haplotypes) were identified for amplified fragment. The frequencies of SSCP patterns of polymorphic fragment were 0.09, 0.17, 0.37, 0.14 and 0.23.The relation between the different haplotypes and body measurements including body length (BL), heart girth (HG), height at withers (HW), height at back (HB), rump length (RL) and scrotal circumference (SC) were ascertained in all of the analyzed animals. According to our results, there is significant association between the different haplotypes of this fragment with additive estimated breeding value for the HG and RL traits. These results confirmed the potential usefulness of leptin gene in marker-assisted selection programs for sheep breeding in Makooei sheep breed.

Identification of Simple Sequence Repeat Markers that Differentiate Bermudagrass Cultivars Derived from ‘Tifgreen’

The release of the bermudagrass (Cynodon spp.) triploid hybrid ‘Tifgreen’ revolutionized southeastern U.S. golf course greens. Off-types within this cultivar began to be identified soon after the initial plantings, and through the last 50 years, many of the best performing off-types have been released as new cultivars. Examination of some of the most popular somatic mutants with a new set of 47 simple sequence repeat (SSR) markers and 23 previously discovered genomic SSR markers identified five polymorphic fragments (as compared with ‘Tifgreen’) among three cultivars, TifEagle, MiniVerde, and Tifdwarf. Each polymorphism appears to be a slight increase/decrease in microsatellite repeat number and the polymorphic fragments are unique for each cultivar. Two polymorphic fragments were identified that were unique to ‘Tifdwarf’, one polymorphic fragment was unique to ‘TifEagle’, and two polymorphic fragments were unique to ‘MiniVerde’. Furthermore, three of the five polymorphic markers display an additional allele only in the shoot tissue but not in the root tissue of ‘TifEagle’ and ‘Tifdwarf’. This finding suggests that ‘TifEagle’ and ‘Tifdwarf’ are somatic chimeras. This set of SSR markers identifies repeatable polymorphic fragments among multiple ‘Tifgreen’-derived cultivars and gives insight into the nature of the mutations that exist within ‘Tifgreen’.

Development of a PCR marker for rapid identification of the Bt-10 gene for common bunt resistance in wheat

In western Canada, the Bt-10 resistance gene in wheat (Triticum aestivum) is effective against all the known races of common bunt caused by Tilletia tritici and T. laevis. The genotypes of 199 F2 plants, originated from a cross between BW553 containing Bt-10 and the susceptible spring wheat cultivar 'Neepawa,' were established in greenhouse and field inoculation studies. A ratio of 1:2:1 resistant : heterozygous : susceptible was observed for bunt reaction, indicating that Bt-10 was expressed in a partially dominant fashion. A polymorphic DNA fragment, amplified using RAPD, and previously shown to be linked to Bt-10 was sequenced and SCAR (sequence characterized amplified region) primers devised. However, SCAR primers failed to amplify the polymorphic fragment. Restriction of PCR products with DraI revealed a polymorphic fragment of 490 bp resulting from a single base pair difference between lines possessing Bt-10 and those lacking the gene. As per the base pair difference, FSD and RSA primers were designed to generate a 275-bp polymorphic DNA fragment. Both 275- and 490-bp polymorphic fragments were present in all of the 22 cultivars known to carry Bt-10, and absent in all 16 cultivars lacking Bt-10. A 3:1 ratio was observed for presence: absence of the 275-bp marker in the F2 population. Using Southern analysis, the 490-bp fragment was effective in differentiating homozygous resistant plants from those heterozygous for Bt-10, based on its presence and the hybridization signal strength. A 1:2:1 resistant : heterozygous : susceptible ratio was also observed for the molecular marker and corresponded to 88% of the phenotypes deduced from the original F2 population. The molecular marker was estimated to be between 1.1 cM and 6.5 cM away from the Bt-10 resistance gene, based on the segregation analysis. Segregation analyses of Bt-10 and the 275-bp marker, evaluated in three different Canada Prairie Spring (CPS) wheat populations, demonstrated a segregation ratio of 3:1 for the molecular marker in two of the populations. These results demonstrated that the PCR marker system using the FSD and RSA primer pair permitted a rapid and reliable identification of individual lines carrying the Bt-10 gene for resistance to common bunt. Key words: resistance gene, genetic segregation, molecular marker, RAPD analysis.

Factor XII gene alteration in Hageman trait detected by TaqI restriction enzyme

A cDNA for coagulation factor XII has been used to investigate the presence of gene lesions and restriction fragment length polymorphisms in two brothers with Hageman trait and their family. A TaqI polymorphic fragment has been found in the two propositi and in 11 members of the paternal lineage. This polymorphism, absent in the normal population, is correlated with the reduction of factor XII activity and enables the identification of heterozygous factor XII deficiency. Factor XII gene deletion as the cause of Hageman trait in this family has been excluded. A restriction map has been constructed, and the TaqI polymorphic site has been localized within the 5′ portion of the gene. The mutation in the polymorphic site is probably the cause of the factor XII deficiency. Data suggest the presence of one factor XII gene per haploid genome.

Factor XII gene alteration in Hageman trait detected by TaqI restriction enzyme

A cDNA for coagulation factor XII has been used to investigate the presence of gene lesions and restriction fragment length polymorphisms in two brothers with Hageman trait and their family. A TaqI polymorphic fragment has been found in the two propositi and in 11 members of the paternal lineage. This polymorphism, absent in the normal population, is correlated with the reduction of factor XII activity and enables the identification of heterozygous factor XII deficiency. Factor XII gene deletion as the cause of Hageman trait in this family has been excluded. A restriction map has been constructed, and the TaqI polymorphic site has been localized within the 5′ portion of the gene. The mutation in the polymorphic site is probably the cause of the factor XII deficiency. Data suggest the presence of one factor XII gene per haploid genome.