1) DNA-Most of it is found in the cell nucleus, some of it is found in mitochondria. It has four chemical bases-A (Adenine), G (Guanine), C (Cytosine), and T (Thymine). A and T pair up and then C and G pair up within a strand. These chemical bases are the "rungs" of the ladder they form. The vertical sides of the ladder are formed with sugar and phosphate molecules. Together, they create the double helix. DNA strands can replicate themselves.
2) Splicing-One part of an organism's DNA is cut out and replaced with another organism's DNA.
3) Hybrid-When two or more organisms form a new organism. Happens naturally with plants and sexually with animals. It also happens inside of a lab. Sometimes hybrid animals are called chimeras. Manmade hybridization is being done right now in some countries that allow human/animal cross breeding. There are several ways scientists can go about it such as fertilizing animal eggs with human sperm or implanting animal eggs with human genes.
4) Genetic Modification: I learned a great deal about this when writing Big Pharma, Big Agri, Big Conspiracy. Food is the best example of how this is used. Monsanto Corporation is the international king of perfecting this new kind of food into agriculture. The general concept consists of splicing genes that protect crops from bugs, drought, frost, etc., into crops that are vulnerable. The modification could also make certain foods bigger, such as Franken-fish or giant farmed salmon. Can we genetically modify ourselves with other genes that will help us live longer, be more healthy, or even reverse disease? Yes. Designer babies will be here in 2017. Right now scientists claim to be able wipe out a degenerative eye disease with gene therapy (another fancy term that essentially means gene modification).
Is it possible to splice a human and alien? It sure looks that way!