Hang Loose Bruce's picture
I inquired about genetic engineering of fodder crops and received this answer: "Molecular approaches to improvement of guinea grass, an important tropical and subtropical forage for cattle, have included genetic sequencing and marker-assisted breeding. To our knowledge, genetic engineering has not yet been undertaken." Please define "genetic sequencing and marker-assisted breeding". How do these techniques differ from genetic engineering? Thanks

A:Expert Answer

The genes that make up the blue print for an organism are carried on its DNA, which consists of a string with information coded much like letters and words. Genes or sets of genes determine many of the physical and biochemical characteristics of the organism – for example a gene for growth rate, or a set of genes that make a plant drought tolerant. Genetic sequencing is the determination of the precise DNA sequences that make up the genes of an organism (the Human Genome Project is the most famous example of this).  Using this information, researchers can identify certain DNA elements that are associated with particular plant characteristics of interest (“molecular markers”). Breeders can then use these markers to quickly identify individual plants that have the desired characteristics without having to actually grow the plants in the field.  Breeders choose individual plants for breeding that have the markers for the characteristics they need and quickly set aside the plants that do not. This is called “marker assisted selection” or “marker assisted breeding”. This technique allows breeders to cross-breed individual plants to efficiently and reliably add desired characteristics to particular crop varieties. By contrast, genetic engineering involves directly changing the DNA sequences to alter or add to the plants’ genes and create new characteristics.

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WillingToListen's picture

I would assume it means that they don't add additional traits, they just rearrange what is already present or breed two crop types to create a better outcome. I am not a scientist, but that is kind of what it sounds like.

WheatLover's picture

I think it is more along the lines of figuring out the order in which the DNA's nucleobases (guanine, adenine, thymine, and cytosine) are arranged, and then figuring out which sequences are linked to which traits.

jtrav21's picture

Bruce - have you done any web searching yourself to look this up?

Here is the wikipedia article on marker assisted breeding: http://en.wikipedia.org/wiki/Marker-assisted_selection