How is genomics helpful in the real world? I mean, really, what good does it do to anyone to know a bunch of strings of 4 letters (ie; ATGGTACCATG)?
Understanding how individual genes affect a particular trait (such as height or likelihood of developing heart disease) turns out to be very complex. Not only are many genes likely to be involved with any one trait, but they interact with each other AND with their environments. This makes predictions of functionality quite difficult.
Genomics is complex stuff, but it can still be incredibly informative. There are many useful applications of genomics to real-world problems.
One example includes criminology. Each individual has unique DNA (slightly different string of bases), though relatives will have more similar DNA than 2 random strangers. If there is DNA evidence from the scene of a crime that matches individual A, this provides fairly clear evidence that individual A was at least in the room (assuming that no laboratory experiments or mix-ups were made).
Another very different example of the utility of genomics, often employed in agriculture, is called "marker assisted selection" or "marker assisted breeding." In early agricultural history, humans would take the offspring from the "best" producers, such as those corn plants that made the largest, sweetest kernals or those goats that produced the most milk. Over many generations, this form of selection produced evolutionarily distinct products that suited the farmers. An example of this is the evolution of a branchy, small-seeded grain called teosinte into what is now known as modern maize (corn) which produces seeds over 100 times the size and weight of the teosinte ancestor's seeds.
This breeding strategy has been effective, but also has caveats. One is that it typically takes decades to produce a desirable final product, depending on the generation time. Another is that different traits may be preferred in different climates or by different farmers. Still another problem is that breeding for certain favored traits may cause other detrimental consequences at other particular traits.
Along comes genomics. Genomic data provides a unique blueprint of DNA code for all varieties of any organism one chooses to sequence. Statistical methods can link traits (such as big seeds) and particular genomic sequences. If we identify the genes or genetic regions associated with a desired phenotype, it is possible to then use this information for breeding desired traits. Seeds or seedlings can be "genotyped" (identified with genetic markers already shown to be linked to the trait of interest) and chosen for growing. For perennial plants or trees, this eliminates many years of the breeding process, since plants no longer have to be grown to maturity to assess their desirability. In addition, one can simultaneously select for many different traits in an individual or avoid undesirable side-effects, such as reduced fertility (as long as these traits were previously measured and linked to unique genetic markers).
Another bonus revealed by genomics is that organisms often find more than one way to make a particular trait. Imagine you have 100 corn plants with large seeds. Genomic information from each of these individuals reveals that there are 4-5 unique genetic signatures to "large seed" phenotypes. This information enables modern plant breeders to select for the desired trait in multiple ways, encouraging greater genetic diversity of desired cultivars.
