DNA Molecules in Moss Open Door to New Biotechnology

ScienceDaily (Nov. 22, 2009) — Plasmids, which are DNA molecules capable of independent replication in cells, have played an important role in gene technology. Researchers from Uppsala University in Sweden have now demonstrated that plasmid-based methods, which had been limited to single-cell organisms such as bacteria and yeasts, can be extended to mosses, opening the door to applications of a number of powerful techniques in plant research.

Professor Hans Ronne's research team at the Department of Medical Biochemistry and Microbiology at Uppsala University works with the diminutive Physcomitrella moss, which is widely used in research because its genes are easier to "knock out" than those of other plants. Previous work has also shown that DNA introduced into Physcomitrella cells is capable of self-replication through an as yet uncharacterised process.

The new study, which was led by Dr. Eva Murén and Ph.D. student Anders Nilsson, shows that plasmids introduced into moss cells can be rescued back to bacteria without affecting the plasmids' original structures, provided that certain conditions are met. Up to now, various kinds of rearrangements have sharply limited the use of plasmids in animal- and plant-cell research.

"Our work with plasmids in moss suggests that it will be possible to use powerful methods such as gene cloning by complementation and overexpression directly in plant cells without recourse to single-cell organisms like bacteria or yeasts," says Professor Hans Ronne. "This, in turn, may simplify basic and applied research and biotechnology involving plants."

Journal Reference:

Muren et al. Rescue and characterization of episomally replicating DNA from the moss Physcomitrella. Proceedings of the National Academy of Sciences, 2009; DOI: 10.1073/pnas.0908037106

Carine Mugeni:42293370

Haemoglobin genetic variation can lead to increased parasite transmission to mosquito vector in Malaria

It has been known for some time that genetic variations in haemoglobin protect some people from dying from serve strains of malaria. New research however is showing that this same genetic variation can lead to increase transmission of the pathogen from the human host to mosquito vector. The study examine 3869 that fed on humans of now genotypes had feed on individual with a known haemoglobin genotype. After 7day the mosquitoes where cut open and the scientists examined the number of mosquitoes infected. Infection rates of individuals that feed on haemoglobin with the genetic variation type C or AC or CC. C being the variant where significantly higher than those that feed on normal genetic haemoglobin AA.

Can gene swapping save our children from inherited diseases?

1 in every 6,500 child are at risk to a range of mitochondrial diseases. These disorders have a range of severity and can cause muscle weakness, blindness, heart and liver failure, diabetes and learning disabilities.
These diseases are caused by the mutation in the minute amount of DNA found in the mitochondria. The mitochondria DNA are independent from the DNA found in the nucleus of the cell thus hinting towards the possibility that gene swapping could be used to produce healthy fertilised eggs.
Researchers from the University of Newcastle did just that. There were able to come up with a pioneering technique that allowed them to transfer healthy genetic material in the nucleus from women suffering from mitochondrial diseases into the eggs of women donors who were unaffected. Therefore any child born using this technique would now have a functioning mitochondria and their genetic make-up would come entirely from the mother's and father's DNA.
Previously, women who found out that they were carriers of mitochondrial disease were forced to make painful decisions. They could either opt to remain childless or risk passing on the disease to their child. Once affected, the effects would remain with the child for the rest of their life as the disorders are so far incurable.
Thus advancement in this aspect has an immense potential in helping women suffering from mitochondrial disease and give them a chance in starting a healthy family by preventing the onset of such diseases in the first place. They will not have to make painful decisions in having a child who may have the disease. Hopefully this technique can help end the tragic relationship where a mother has to pass on the disease to her children.

Source: http://www.guardian.co.uk/science/2010/apr/14/scientists-gene-swap-technique-disease

Posted by Daniel Yew (41947809)

Development of genetic markers in celery based on restriction fragment length polymorphisms

Linkage relationships are reported for 34 markers in celery (Opium grave lens L. vary ‘dulcet’) including 21 RFLP, 11 isozyme, and 2 morphological traits. The mapping was carried out in a cross between celery and an annual accession from Thailand, A143, and based on F 2 segregation of 136 plants. A total of 318 centiMorgans (cM) are covered by the markers distributed in 8 linkage groups. Probes for the identification of RFLPs were isolated from a celery cDNA library and were also obtained from heterogonous sources. Eco RV, Eco RI, and Hind III were the most useful restriction enzymes in uncovering polymorphism. In our cross, 18% of the cDNA probes were found to be polymorphic for at least one of the enzymes used. Six of the markers showed significant deviations from expected F 2 ratios.
Genetically marked tissues of celery (Opium grave lens) were employed to contrast genetic and chromosomal stability in serially bulk-transferred callus and regenerated plants. After six months in culture, 84% of the callus cells were karologically indistinguishable from normal, while the remainder exhibited chromosome loss and/or fusion. All of 50 clones derived from this tissue expressed the control phenotype with respect to heterozygous isozyme markers. Of 95 plants regenerated from the same tissue, 94 were phenotypic ally indistinguishable from the original explants donor, and cytogenetic analyses revealed the presence in 4.3% of an accessory chromosome, while the remainder were normal diploids. Analysis of the shelfed progeny of these regenerated plants revealed the presence of a new recessive mutation causing abnormal leaf morphology at a frequency of 1.8%. Only one of 40 cells in 12-month-old callus tissue was karyologically indistinguishable from normal, the remainder consisting primarily of hypo diploids. The observation that all 50 clones were phenotypic ally heterozygous was statistically inconsistent with the hypothesis that hypodiploidy was associated with random complete chromosome loss. The culture had, at this point, lost the ability to regenerate. It is speculated that embryogenic cloning of celery may be suitable under certain circumstances for direct field establishment, but that levels of new genetic variation are sufficiently high to preclude its use for seed production.

Sources:
http://deepblue.lib.umich.edu/handle/2027.42/46011
http://www.springerlink.com/conten
Images:
http://alternativeremedies.wordpress.com/


Aida Emami (41715923)