Genetics are a super popular subject in TV shows, movies and even comics. Kind of expected really, because genetics are just perfect for letting the imagination run wild and for generating lots of drama. Here are some popular plots where genetics play a main role and how close to reality these scenarios might be
A genetic mutation gives a person or animal some unique ability. The various heroes and villains in X-Men were born with, or acquired, unique appearances and superpowers. "Beast" was, as a youngster, a particularly large guy with superhuman strength, agility and speed (Marvel, 2010). His unusual characteristics, or "mutations" were the result of his father's exposure to radiation. Despite being teased in school because of his appearance, his abilities made him a great football player. Later on, he becomes a genetic researcher and discovers a "hormonal extract" that causes "genetic mutation." In order to disguise his appearance to stop a villain, he takes the extract himself and mutates into the blue furred beast in the later publications of the comic series.
In truth however, most mutations have only a tiny effect, or, quite often, no effect at all. Some, however, are detrimental, maybe even lethal—it all depends on where in the DNA the mutation takes place and whether or not it changes the structure or function of the protein the gene codes for. Radiation does often lead to mutations – in fact researchers often make use of this fact to study gene function using simple organisms such as flies. Groups of flies are exposed to radiation that generates mutations in their sex cells which will be passed on to their descendents. After breeding the irradiated flies, their offspring are screened for mutant phenotypes, such as changes in eye color, wing shape, or body pigmentation (all of which have been found using this method). After identifying the genes that mutated, scientists can then study how disrupting their normal function affects development and thus learn about how different genes work together. Also, "Beast's" scientific discoveries are far from any real possibility: to date, no "mutagenic hormonal extract" exists that is capable of physically transforming anyone or anything into a different creature!
Instead of wondering if their baby will be a boy or a girl, or what color her eyes might be, parents just get to order their child with custom genetics to fit their dreams and ambitions. The movie "Gattaca" (1997) is based on this premise. In the movie, human genetic engineering is prevalent, but not accessible to everyone. Genetic makeup defines social class, so people conceived naturally are at a disadvantage. One man's dreams are hindered by his "inappropriate" genotype—so he borrows someone else's to fool the system. The novel "A Brave New World" (Aldous Huxley) also explores certain aspects of designer humans. In a futuristic society, reproduction is fully regulated. Practically no child is conceived naturally; instead babies develop in synthetic setups and their development is tightly controlled.
In reality, we might not be too far from pre-determining some traits in unborn children. It might not ever be possible to choose every aspect of an individual's characteristics by manipulating her genetic background (remember, not everything is determined by our genes) – but even now it is possible to define a few things. For example, using in vitro fertilization procedures, it is possible to define the sex of an embryo. As it turns out, because in humans the X chromosome is so much larger than the Y chromosome, it is possible to detect simply by the amount of DNA it contains which sperm cells have an X or a Y chromosome.
By screening and choosing specific sperm cells, it is possible to pre-define the sex of a baby. There may be a specific medical reason for wanting to do so, such as to avoid passing on potentially fatal hereditary diseases such as hemophilia and muscular dystrophy, but there is a growing concern worldwide that the non-medical sex selection of embryos may end up dangerously skewing the proportions of male and female children born in certain countries as a result of cultural biases (Robertson, 2003; Stump, 2011).
A detective fools a suspect into giving up his DNA by collecting saliva from his discarded chewing gum. The process is quick and easy – the chewing gum goes into a little tube with some colorless liquid, and then into some magical machine that prints out some banding pattern or DNA sequence to compare to the sample collected from the crime scene. It is match! Let's go get an arrest warrant…
Believe it or not, with current technological advances it is possible to get enough DNA to analyze from the saliva used to affix a stamp. DNA testing is routinely used for paternity testing, victim identification, and conviction, as in forensic shows. The tests take advantage of genetic variation from individual to individual including, amongst others, variation in regions with variable numbers of the same base-pair sequence (variable number of tandem repeats, VNTR), single nucleotide polymorphisms (SNP) and mitochondrial DNA. What the shows often misrepresent is just how long the process takes and how the DNA information might be interpreted. In the shows, the whole process has a couple of steps and appears to take only a few minutes. In fact, there are many steps, and depending on the techniques used for the DNA fingerprinting (and the state of the DNA being used), it might take hours, days, or even weeks to get a result. Also, DNA fingerprinting can exclude with certainty a potential suspect, but only identify a perpetrator with a certain probability.