The June 13, 2013 Supreme Court decision that human genes are not patentable should logically be the first step in reversing three decades of decisions that flouted the previously general understanding that Section 101 of Title 35 U.S.C. prohibited patenting of living organisms.
In the case of genetically modified seeds, strands of DNA from flowers, fish and animals and/or a virus are loaded into a gene gun - sort of a specialized pellet gun - and literally shot into the new seed to be modified in hopes that the inserted DNA will be incorporated by it without further intervention, mix with the seed and take hold, and the "new" plant that will grow from this new seed will replicate and reproduce the new DNA in the new seeds after harvesting.
Anything is fair game here; the possible combinations are exponentially high, infinite. GMO patents that have been granted for genetically modified (GM) corn, canola, cotton, sugar beets and soy have their roots in a first case for a patent application filed with the US Patent Office by General Electric (GE), which developed a bacterium capable of breaking down crude oil, to be used in treating oil spills. GE listed one of its genetic engineers, Chakrabarty, as the inventor. 
The application was rejected by the patent examiner, Sidney Diamond, because under patent law it was generally understood that living things were not patentable subject matter under Section 101 of Title 35 U.S.C.
GE appealed to The Board of Patent Appeals and Interferences, which agreed with the original decision. On a subsequent appeal, the US Court of Customs and Patent Appeals overturned the case in GE's and Chakrabarty's favor, writing that "the fact that micro-organisms are alive is without legal significance for purposes of the patent law," thus blatantly disregarding Title 35. Sidney A. Diamond, commissioner of Patents and Trademarks, appealed to the Supreme Court of the United States (SCOTUS) in the Chakrabarty v. Diamond case, which was argued on March 17, 1980. A narrow 5-4 decision was issued on June 16, 1980. The patent was granted by the USPTO on March 31, 1981. 
SCOTUS thereby handed corporations the right to patent life, bacteria, seeds, plants, and animals in a misguided decision, which again ignored Title 35's exclusion of all patents on life and living organisms. While the manipulation process was new, all of the original existing DNA and all receiving DNA from whatever provenance are not.
Genetic material constitutes the inalienable property and inheritance of all humankind, as it has evolved in a wondrous process in nature that took billions of years, a process in which corporations did not participate in the least - nor could they have. Neither the receiving gene-spliced DNA, which constitutes 99.999% of all the genetic material involved in the process, nor the spliced infinitesimal amount of DNA used in the process can be claimed as the inventor's property. In this light, patents on life constitute the theft, in plain daylight, of the natural patrimony and inheritance of the world, which belongs to all of humanity, by and for the exclusive use and profit of a very few. The words do exist in the vocabulary and in the historical record for this type of action: dictatorial fascism, the collusion of corporate interests with the dictatorial coercive powers of the State. 
On June 13, 2013, the SCOTUS light bulbs suddenly went on, and on a unanimous vote (9-0), the court rejected a patent application for two cancer genes isolated by Myriad Genetics, Inc. In the court's opinion written by Justice Clarence Thomas, Title 35 was repeatedly invoked as "...we hold that a naturally occurring DNA segment is a product of nature and not patent eligible merely because it has been isolated..." This is, finally, the right decision. 
GMOs are just the reverse of this case, i.e., DNA is combined instead of being isolated, thus logically also not patentable just because two or more DNA segments have been mixed together.
The doors are now open to reverse all previous 30 years of wrongdoings and false GMO patents and end the absurdity that everything in life, the food that we eat, plants, microbes, viruses, fish and animals can ultimately be patented and owned by someone else. GMO patent insanity has already led to crimes against humanity, and crimes against the planet.
The horrifying Frankensteinian effects of GMO foods on animals and plants are now being discovered by Serallini, Carman and other studies. The case is not over; it just started. So let's get busy. Maybe this is a good time to be an attorney. Life, nature, all living things, the human body, whole or in parts are not patentable, ever.
Never were, never will be. May this be a lesson to all who foolishly thought they could steal from the patrimony of life.
 Diamond v. Chakrabarty, 447 U.S. 303 (1980), SCOTUS.
 Pereira, T. (2012). The Transition to a Sustainable Society: A NewSocial Contract. Environ Dev Sustain 14:273–281.