Genetic variation of CAST gene in Local Karnobat and Karnobat merino sheep breeds

Karnobat sheep plays an important role in the development of sheep breeding in Southeastern region of Bulgaria. They are valuable source of genetic material. The aim of present experiment was to determine the allele variation of CAST gene in Local Karnobat and Karnobat Merino sheep breeds. A total of 60 blood samples were collected – 30 per breed. DNA was extracted and genotypes of all animals were identified by means of PCR-RFLP technique. The restriction reactions were accomplished by specific enzyme MspI. As expected both breeds were characterized with low level of genetic diversity due to the fact that mostly maintaining selection has been implemented. In Local Karnobat sheep breed was identified only one heterozygous individual from all 30. In Karnobat merino were identified allele M with frequency 0,97 and allele N with frequency 0,03. Genotypes MM and MN were revealed with frequencies 0,93 and 0,07, respectively. According to the statistical analysis both breeds were in HWE equilibrium.

Association of selected polymorphic sites in the IGF1R gene with body weight and conformation of Hereford cattle

The aim of this study was to determine the relationship between selected polymorphic sites located in various fragments of the IGF1R gene and the growth and development of Hereford cattle. Variation in the gene was identified using the PCR-RFLP and ACRS-PCR methods. The herd showed no variation at the IGF1R/i4/Mph1103I site (monomorphism), but in the case of IGF1R/e7/TaiI polymorphism, one heterozygous individual was observed, while the others had the CC genotype. In the case of IGF1R/e21/TaqI and IGF1R/ i4/HinfI, significant differences were only noted for birth weight (P ≤ 0.01; (P ≤ 0.05). In addition, in individuals with the rare genotype (TT), the lumbar spine was higher, overall body weight was greater, and calving took place earlier.

Mutation rate analysis via parent–progeny sequencing of the perennial peach. I. A low rate in woody perennials and a higher mutagenicity in hybrids

Mutation rates vary between species, between strains within species and between regions within a genome. What are the determinants of these forms of variation? Here, via parent–offspring sequencing of the peach we ask whether (i) woody perennials tend to have lower per unit time mutation rates compared to annuals, and (ii) hybrid strains have high mutation rates. Between a leaf from a low heterozygosity individual, derived from an intraspecific cross, to a leaf of its selfed progeny, the mutation rate is 7.77 × 10 −9 point mutations per bp per generation, similar to Arabidopsis thaliana (7.0–7.4 × 10 −9 point mutations per bp per generation). This suggests a low per unit time mutation rate as the generation time is much longer in peach. This is supported by our estimate of 9.48 × 10 −9 point mutations per bp per generation from a 200-year-old low heterozygosity peach to its progeny. From a more highly heterozygous individual derived from an interspecific cross to its selfed progeny, the mutation rate is 1.38 × 10 −8 mutations per site per generation, consistent with raised rates in hybrids. Our data thus suggest that (i) peach has an approximately order of magnitude lower mutation rate per unit time than Arabidopsis , consistent with reports of low evolutionary rates in woody perennials, and (ii) hybridization may, indeed, be associated with increased mutation rates as considered over a century ago.

Isolation and inheritance of microsatellite loci in the Dungeness crab (Brachyura: Cancridae: Cancer magister)

The isolation, PCR amplification, and descriptive statistics of six microsatellite loci are described for the Dungeness crab, Cancer magister. Also reported is the inheritance of these loci in two families obtained from artificial crosses in the laboratory. All six loci conform to expectations under Mendelian inheritance and there is no evidence for linkage between any of the loci. Allelic size ranges for three of the loci are relatively large, ranging from 135–357 bp between the smallest and largest allele detected at that locus. At two of these loci upper allelic drop out (non-amplification of the larger allele in a heterozygous individual) can be problematic for scoring. Results from cross-species amplification in nine congeners are summarized. These loci will be valuable in studies requiring high-resolution genetic markers in Dungeness crabs and related species.Key words: Cancer magister, microsatellite, Mendelian Inheritance, cross species amplification, Brachyura.

Genetic localization and phenotypic expression of X-linked cataract (Xcat) in Mus musculus

SummaryLinkage data relative to the markers tabby and glucose-6-phosphate dehydrogenase are presented to locate X-linked cataract (Xcat) in the distal portion of the mouse X-chromosome between jimpy and hypophosphatemia. The human X-linked cataract-dental syndrome, Nance–Horan Syndrome, also maps closely to human hypophosphatemia and would suggest homology between mouse Xcat and human Nance-Horan Syndrome genes. In hemizygous males and homozygous females penetrance is complete with only slight variation in the degree of expression. Phenotypic expression in Xcat heterozygous females ranges from totally clear to totally opaque lenses. The phenotypic expression between the two lenses of a heterozygous individual could also vary between totally clear and totally opaque lenses. However, a correlation in the degree of expression between the eyes of an individual was observed. A variegated pattern of lens opacity was evident in female heterozygotes. Based on these observations, the site of gene action for the Xcat locus is suggested to be endogenous to the lens cells and the precursor cell population of the lens is concluded to be small. The identification of an X-linked cataract locus is an important contribution to the estimate of the number of mutable loci resulting in cataract, an estimate required so that dominant cataract mutagenesis results may be expressed on a per locus basis. The Xcat mutation may be a useful marker for a distal region of the mouse X-chromosome which is relatively sparsely marked and the X-linked cataract mutation may be employed in gene expression and lens development studies.