Cassava genome investigation

Cassava is a root crop that is easy to grow and drought resistant, making it an important food crop in many parts of the world.  It is also a good source of the starch needed to generate ethanol fuel.  However, cassava is vulnerable to plant pathogens, resulting in decreased yields.  In an effort to develop breeding strategies that can improve cassava's disease resistance and increase crop yields, a team of researchers from the University of California, Berkeley and the DOE Joint Genome Institute have compared the genomes of different cassava varieties to each other and to related plants including Ceara rubber and castor bean.  They found that cassava currently cultivated in Africa has reduced genetic variation, and that the Ceara rubber had been previously crossed with the cassava plant, leading to "elite" cassava varieties with an increased number of desirable traits, as well as determining genetic relations between cassava varieties.

This article originally caught my attention because of its implications for renewable energy. This plant is especially important because it is a staple crop, so these efforts to increase genetic variation in cassava are encouraging.  Hopefully, knowing the genetic differences between varieties will expedite the process of increasing genetic variation, specifically in areas that would give cassava increased disease resistance.  Perhaps another cross with the Ceara rubber plant could be used, since this cross was successful in the past.

DNA Sequences Reveal Insight on Redwoods

     Coast redwoods are the tallest trees in the world.  However, they also have another magnificent trait, they can sprout from fallen logs, roots and even sprouting from cut stumps.  Researchers from the University of California, Berkeley are uncovering information about patterns of coast redwood clones with a new DNA analysis method. This new method could help forest management and preservation efforts.  The new method will let scientists identify clonal lineages and study how clonal diversity varies throughout the range of species.  Coast redwoods are among the oldest living trees on earth and very little research has been done with the clonal patterns of the coast redwoods.  This is somewhat due to the fact that they are hexaploid, or they have six copies of each homologous chromosome instead of two.
     Lakshmi Narayan, the grad student who is leading the UC Berkeley study says that in addition to the hexaploid condition they also have another challenge that the genotypic identity of clonal plants could possibly cause somatic mutations.  Narayan has designed a new protocol to overcome challenges associated with mutations and the high genetic copy number in the redwood DNA.  Narayan and her team collected DNA from 770 redwoods and have identified about 449 distinct clones.  The key to this new method is the use of short repeating DNA sequences.  The short DNA sequences, known as microsatellites, are present in all living organisms and widely used to distinguish individuals from one another.
     Hopefully this new method will shed light on other species which are still under investigation.  The new method of studying the short DNA sequences might give researchers a better understanding of the redwoods which are such old plants.  We could potentially study how they live so long giving us a better understanding on preserving other species.

Original Article