Genetics in the Third Millennium
Volume:12 Issue: 2, 2014

Heredity hearing loss (HL) is the most prevalent sensory disorder and most cases are non-syndromic. Eighty percent of non-syndromic sensorineural deaf patients show an autosomal recessive pattern of inheritance. To date، 47 genes and 98 loci have been reported for this mode of inheritance. Previous studies in our center showed the high prevalence of DFNB3 among Iranian deaf families. PJVK (DFNB59) is the first human gene implicated in non-syndromic deafness due to a neuronal defect. PJVK encodes Pejvakin، which is present in the auditory nerves and brainstem. Scientists believe Pejvakin can play an important role in transmission of nerve impulses that register sound. The aim of this study was to investigate the prevalence of DFNB59 mutations among 36 unrelated deaf Iranian families. We selected 36 consanguineous deaf families with two or more affected individuals who were negative for mutations in GJB2. At first، we conducted homozygosity mapping using four STR markers for DFNB59 and finally، for the families that showed autozygosity by descent، we performed Sanger Sequencing for all exons via intronic primers flanking the exons. One family showed autozygosity by descent at DFNB59 locus and Sanger Sequencing of the family revealed c: 499C>T transition، which produces a premature stop codon (R167X). So far، ten different types of mutations have been reported for Pejvakin gene. In 2007، R167X was first reported in a Turkish family. This study revealed the first case of R167X among Iranian population and it seems that the mutation in Pejvakin is more prevalent in Iran than other countries، because most cases have been reported among Iranian population.

The most common sensorineural defect in human is congenital hearing loss and genes have an incontestable role in the development of this defect. Many genetic mutations are known to be responsible in this heterogeneous disease. The most frequent mutations are GJB2 mutations followed by the SLC26A4 mutations. Recently، we published a report regarding the role of c. 637+1G>T mutation in CABP2 gene، causing hearing loss in three Iranian families. The present study was launched to analyze the role of this recently reported mutation in patients with sporadic hearing loss. One hundred and eighty three patients with moderate to profound sporadic hearing loss were included in this study. The mutation c. 637+1 G>T was investigated in patients using the PCR-RFLP method. PCR-RFLP findings revealed that the considered mutation was absent in subjects with sporadic hereditary hearing loss. The mutation c. 637+1 G>T in CABP2 gene did not play any roles in the investigated Iranian patients with sporadic hearing loss. Larger samples of different populations، and assessment of all exons and the promoter region of mentioned gene will help to determine the real role of this gene in producing hearing loss.

In order to study STAT5b gene polymorphisms and its association with milk production traits in Holstein dairy cows in Khorasan Razavi Province، blood samples were collected from 150 Holstein cows from six herds in Khorasan Razavi Province. DNA was extracted using modified the salting out-Chloroform method and polymerase chain reactions (PCR) were carried out by specific primer pairs for amplification of a fragment of 337 bp from part of exon 16 of STAT5b gene. All animals were genotyped by single stranded conformation polymorphism (SSCP) analyses by Acrylamide gel and using silver staining. Five SSCP patterns (genotypes) of AA، BB، CC، AB، and AD were identified with the frequencies of 0. 0667، 0. 1933، 0. 2067، 0. 4466، and 0. 867، respectively. Statistical data was analyzed using the POPGENE software. Chi-square test (χ2) showed that this population was not in the Hardy-Weinberg equilibrium. Effective allele numbers (Ne) and Shannon’s information index (I) were 3. 0366 and 1. 1928، respectively. Results showed that SNPs were significantly associated with milk yield in Khorasan Razavi Holstein cows (P <0•0004). The cows with combination genotype CC had the highest milk yield. These results suggested that the STAT5b may be a potential genetic marker for milk production selecting. The association between polymorphism in this gene with milk fat and milk protein percentage was not significant

The purpose of the study was to investigate the nucleotide sequence of the Cytochrome C oxidase 1 gene (MT-COX1) in the Khorasan’s native chicken and identification of possible mutations in it. For this reason، the MT-COX1 gene was cloned using the specific amplification initiators and cloned in the plasmid pTZ57R/T vector in DH5α strain of E. coli – bacteria after sampling and extracting the DNA from the whole blood. Finally، the recombinant plasmid was extracted from a recombinant colony and its sequence was identified after the purification. The results of the nucleotide blast of this peer showed 99 percent similarity to the same nucleotide sequences of the Gallus Gallus (access number x52392. 1). The comparison of these sequences also revealed six nucleotide differences. However، only three mutations resulted in production of non-synonymous amino acids. The results of the protein blast also presented 99 percent similarity in 100 percent length to the conserved area of subunit 1 in domain cytochrome C oxidase in Gallus Gallus. Furthermore، it was showed that Khorasan’s native chicken had 96% similarity in protein sequence of gene MT-COX1 to the other poultry breeds.

Based on genetic studies, single nucleotid polymorphisms have a pivotal role in the superfecundity and ovulation. Bone Morphogenetic Protein 15 (BMP15) gene, which is essential for fertility, has been maped to the X chromosome. BMP15 has several point mutations. The aim of this study was to determine FecXB and FecXG mutations in Kamouri Goats of Khouzestan Province. For this study, 40 blood samples were collected by vacutainer tubes containing EDTA (Ethylenediaminetetraacetic acid). DNA was extracted by the modified method. The site of the mutations was amplified using specific primers and 153 and 142 bp PCR products were determined for FecXB and FecXG, respectively. Then, the PCR products were digested with DdeI and HinfI enzymes. All PCR products were cleaved by the enzymes. Therefore, no mutations were observed in FecXB and FecXG in the Kamouri goats of Khouzestan Province. In conclusion, the mutations of FecXB and FecXG do not cause prolificacy in Kamouri goats.

This study aimed to investigate the myostatin gene polymorphisms and their relationship with twining trait in 150 individuals from Markhoz goat of Iran. A 573 bp fragment of the myostatin gene was amplified، which contained a deletion 5 bp indel (206 TTTTA/) and a single nucleotide polymorphism substitution (339 T/A) in 5`UTR and exon1 regions، respectively. The PCR products were separately digested for each position using DraI or HinIII restriction enzyme endonuclease. The digestion results revealed two AA and AB genotypes in 5`UTR region and three AA، AT، and TT genotypes in exon1 region of myostatin gene. Odds Ratio (OR) statistics for twinning trait was estimated 1. 4 (P>0. 05) and 4 (P<0. 1) in the first parity compared to the second and third parity، respectively. Also، the odds ratio was 4. 60 (P<0. 05) when the second parity was compared to the third parity. The amounts of OR and Chi-square statistics for the twining rate were 1. 84 and 13. 6 for the AA genotype on theTT genotype and also 0. 28 and 8. 46 for the TT genotype on AT genotype. The OR of the twining rate was estimated 0. 07 (P<0. 1) for the AB genotype compared to the AA genotype in 5`UTR region. The results of this research confirm a significant association between the myostatin gene and the twining rate in Markhoz goats and suggest more investigation in this field on other Iranian native goat breeds.

Nowadays، the science of genetics and relevant issues have influenced various fields of science، particularly the fields of medical sciences (research and clinical field). Considering the high prevalence of hereditary and non- hereditary genetic disorders، especially in our country due to the relatively high prevalence of consanguineous marriages، application of genetic testing for diagnosis، treatment، prognosis، etc. is of considerable importance. However، evolution in the field of genetic testing is very fast and better introduction of different genetic tests can effectively help the scientific community to follow these extensive developments. In this paper، a brief introduction to different genetic tests based on their functional purposes will be provided. In the following، we will present a brief description of the processes، applications، advantages and disadvantages of some of the most commonly used genetic tests in both cytogenetics and molecular genetics fields. In the field of cytogenetics، karyotyping، flow cytometry، FISH، and CGH will be included and in the field of molecular genetics، PCR-based methods، multiplex PCR quantification such as MAPH / MLPA، microarrays and related technologies and next generation sequencing (NGS) will be discussed.

Nowadays، recombinant products have been produced using transgenic animal technology. So far، several techniques have been used to produce transgenic organisms. The most recent of these techniques is SMGT that has been established based on the ability of the sperm to uptake exogenous DNA and transfer it to the oocyte during fertilization. SMGT can be an efficient method when coupled with complementary methods such as electroporation، lipofection، ICSI، REMI and other techniques. The mechanism of the action of SMGT is not well defined. However، it seems that entering exogenous DNA into the sperm genome is a non-random event. The sperm chromatin condenses defines the limited sites for DNA integration. SMGT accompanied by other methods such as electroporation، lipofection، ICSI، REMI and other techniques can be an efficient method، but each of these methods has different efficiency and effects in different species. It is now clear that the sperm has the ability to transfer DNA molecules to egg during fertilization. Recent advances have reported that the efficiency of SMGT is growing and it is a cheap، fast and efficient technique for producing transgenic animals.

microRNAs are small non-coding RNAs which negatively regulate several the expression of target genes at the post-transcriptional level. These non-coding RNAs are involved in different mechanisms including proliferation، differentiation، metabolism، aging، and apoptosis. Deregulation of miRNAs expression is linked with various diseases such as cancer. Human serum and other body fluids are a rich source of biomarkers that can be used in clinical diagnosis. Recently، it has been reported that there are enough stable circulating miRNAs in the serum and body fluids. Therefore، the profile of circulating miRNAs is considered in many studies and is a promising perspective as non-invasive biomarkers. In this review، we will focus on the distribution of circulating miRNAs and their physiological and pathological functions. Finally، some molecular techniques will be presented that are related to detection and analysis of circulating miRNAs as biomarkers.

Since plants are living organisms and cannot escape from biotic and abiotic stresses، they require a regular signaling network for regulation of cellular processes and homeostasis. Reactive oxygen species (ROS) are toxic molecules that can react with vital molecules such as proteins، nucleic acids، lipids، and carbohydrates and cause damage to them. ROS with their unique properties can act as signal molecules that play a role in plant responses. In plants، the signaling role of ROS and cell protection from their toxic effects require a regulatory network and defense systems respectively so that the amount of these factors determine the degree of tolerance. ROS is produced in different organelles like chloroplast، mitochondria، peroxisomes and apoplastic space. The levels of them are regulated by different detoxification mechanisms. ROS is involved in different signaling pathways like MAPK and calcium، and change gene expression patterns in order to respond to stress via specific protein oxidation and affecting transcription factors. In this review، signaling pathway، production، function، and degradation mechanisms of ROS and the effect of ROSs on cell processes like glutathionylation and protein folding under stress conditions are described.