Latest Research News on Genetic Engineering : Nov 2020

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Latest Research News on Genetic Engineering : Nov 2020

November 17, 2020 Biotechnology and Genetics 0

Genetic Engineering of Algae for Enhanced Biofuel Production

There are currently intensive global research efforts aimed at increasing and modifying the accumulation of lipids, alcohols, hydrocarbons, polysaccharides, and other energy storage compounds in photosynthetic organisms, yeast, and bacteria through genetic engineering. Many improvements have been realized, including increased lipid and carbohydrate production, improved H2 yields, and the diversion of central metabolic intermediates into fungible biofuels. Photosynthetic microorganisms are attracting considerable interest within these efforts due to their relatively high photosynthetic conversion efficiencies, diverse metabolic capabilities, superior growth rates, and ability to store or secrete energy-rich hydrocarbons. Relative to cyanobacteria, eukaryotic microalgae possess several unique metabolic attributes of relevance to biofuel production, including the accumulation of significant quantities of triacylglycerol; the synthesis of storage starch (amylopectin and amylose), which is similar to that found in higher plants; and the ability to efficiently couple photosynthetic electron transport to H2 production. Although the application of genetic engineering to improve energy production phenotypes in eukaryotic microalgae is in its infancy, significant advances in the development of genetic manipulation tools have recently been achieved with microalgal model systems and are being used to manipulate central carbon metabolism in these organisms. It is likely that many of these advances can be extended to industrially relevant organisms. This review is focused on potential avenues of genetic engineering that may be undertaken in order to improve microalgae as a biofuel platform for the production of biohydrogen, starch-derived alcohols, diesel fuel surrogates, and/or alkanes. [1]

Genetic engineering of human pluripotent cells using TALE nucleases

Targeted genetic engineering of human pluripotent cells is a prerequisite for exploiting their full potential. Such genetic manipulations can be achieved using site-specific nucleases. Here we engineered transcription activator–like effector nucleases (TALENs) for five distinct genomic loci. At all loci tested we obtained human embryonic stem cell (ESC) and induced pluripotent stem cell (iPSC) clones carrying transgenic cassettes solely at the TALEN-specified location. Our data suggest that TALENs employing the specific architectures described here mediate site-specific genome modification in human pluripotent cells with similar efficiency and precision as do zinc-finger nucleases (ZFNs). [2]

Genetic engineering of livestock

Genetic engineering of livestock is expected to have a major effect on the agricultural industry. However, accurate assessment of the consequences of transgene expression is impossible without multigenerational studies. A systematic study of the beneficial and adverse consequences of long-term elevations in the plasma levels of bovine growth hormone (bGH) was conducted on two lines of transgenic pigs. Two successive generations of pigs expressing the bGH gene showed significant improvements in both daily weight gain and feed efficiency and exhibited changes in carcass composition that included a marked reduction in subcutaneous fat. However, long-term elevation of bGH was generally detrimental to health: the pigs had a high incidence of gastric ulcers, arthritis, cardiomegaly, dermatitis, and renal disease. The ability to produce pigs exhibiting only the beneficial, growth-promoting effects of growth hormone by a transgenic approach may require better control of transgene expression, a different genetic background, or a modified husbandry regimen. [3]

Comparative Analysis of Genetic Structure and Diversity of Sorghum (Sorghum bicolor L.) Local Farmer’s Varieties from Sudan

Aims: Investigate the genetic diversity and structure of 50 Sorghum accessions from 10 different regions in Sudan and one from the county of Central Equatoria in the Republic of South Sudan, by screening 40 RAPD and 10 ISSR (Inter-simple sequence repeat) markers.

Study Design: UPGMA method using  STATISTCA- SPSS software Ver. 9 and PCA using GenAlEx ver. 6.5

Place and Duration of Study: Department of Molecular Biology, Commission for Biotechnology and Genetic Engineering, National Center for Research, Khartoum, Sudan (2010-2012).

Methodology: 47 sorghum accessions with important agronomic traits, representing 10 states in Sudan and three sorghum accessions from the county of Central Equatoria of Republic of South Sudan were assayed for polymorphism using Random Amplified Polymorphic DNA (RAPD) and Inter-simple sequence repeats (ISSRs).

Results: Ten polymorphic RAPD primers distinguished 163 bands. 156 bands were polymorphic among the 50 accessions with 96.6% polymorphism. The seven polymorphic ISSR primers distinguished 78 bands, of which 75 bands were polymorphic with 97% polymorphism. The RAPD distance matrix ranged between 0.07-0.43 which proved wide range of variation, ISSR distance matrix ranged between 0.04-0.47 showing higher genetic variability among the sorghum accessions than the RAPD, whereas, combined data distance matrix for both RAPD and ISSR markers ranged between 0.08-0.39 which reflected more trusted result among Sudanese sorghum accessions. The White Nile state accessions showed the highest percentage of polymorphic loci with 39.75%, whereas lowest was given by Red Sea accessions with 17.99%. The molecular variance within states was 70% and 30% among states.

Conclusion: In conclusion, Results based on combined analysis of both RAPD and ISSR data were most accurate for covering large area inside the genome. White Nile state accessions was the highest in number of bands; number of private bands; percentage of polymorphic loci and heterozygosity (He) mean compared to accessions of other states. [4]


SSR- Based Genetic Diversity Assessment in Tetraploid and Hexaploid Wheat Populations

Molecular analysis for a set of hexaploid (Triticum aestvium) and tetraploid (Triticum durum) wheat cultivars was investigated by applying 11 SSR primers set. The plant materials consisted of 45 genotypes 15 of which were Triticum aestivum and 30 of T. durum obtained from four different regions Egypt, Greece, Cyprus and Italy. PCR products were separated on a 6% denaturing polyacrylamide gel electrophoresis and produced a total of 3840 DNA fragments which were used for the molecular analysis. The estimated parameters computed by POPGENE (Version 1.32) within the two population indicated that the Nei’s genetic diversity (H) was 0.2827, and the Shannon’s Information index (I) was 0.4533 with standard deviation ± 0.0699 and ± 0.0852 respectively. The analysis of population structure revealed that genetic diversity within populations (Hs=0.2761) represented 97.7% of the total genetic diversity (HT=0.2827). The proportion of the total genetic diversity that was attributed to the population differentiation was low (Gst=0.0233) within population. ANOSIM (ANalysis Of Similarities), results showed that R was equal to 0.9048 (P<0.0001) indicated that all the most similar samples of genotypes are within the same population. The wheat varieties from the four distinct regions were clustered according to SSR data into two main clusters, durum wheat varieties and bread wheat varieties, the principal coordinate analysis (PCOORDA) validated the results of the dendrogram. This study showed that the two populations still had moderate considerable level of genetic diversity and show little genetic differentiation among them. Understanding genetic variation within and between populations is essential for the establishment of an effective breeding program concerning the intraspecific and interspecific hybridization. [5]

Reference

[1] Radakovits, R., Jinkerson, R.E., Darzins, A. and Posewitz, M.C., 2010. Genetic engineering of algae for enhanced biofuel production. Eukaryotic cell, 9(4), pp.486-501.

[2] Pursel, V.G., Pinkert, C.A., Miller, K.F., Bolt, D.J., Campbell, R.G., Palmiter, R.D., Brinster, R.L. and Hammer, R.E., 1989. Genetic engineering of livestock. Science, 244(4910), pp.1281-1288.

[3] Pursel, V.G., Pinkert, C.A., Miller, K.F., Bolt, D.J., Campbell, R.G., Palmiter, R.D., Brinster, R.L. and Hammer, R.E., 1989. Genetic engineering of livestock. Science, 244(4910), pp.1281-1288.

[4] K. A. El-Amin, H. and B. Hamza, N. (2016) “Comparative Analysis of Genetic Structure and Diversity of Sorghum (Sorghum bicolor L.) Local Farmer’s Varieties from Sudan”, Journal of Advances in Biology & Biotechnology, 5(3), pp. 1-10. doi: 10.9734/JABB/2016/22735.

[5] Mahdy Abouzied, H., M. M. Eldemery, S. and Fouad Abdellatif, K. (2013) “SSR- Based Genetic Diversity Assessment in Tetraploid and Hexaploid Wheat Populations”, Biotechnology Journal International, 3(3), pp. 390-404. doi: 10.9734/BBJ/2013/4340.

 

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