EvoluTion And SoCiETy 585
models are the basis of mapping genes and mutations in human and other popula-
tions, for example in genome-wide association studies (GWAS). Population genet-
ics, likewise, is the basis for matching DNA evidence with individual suspects in
forensics, paternity identification, and other applications. Evolutionary biologists
developed the models and statistical tests for natural selection in genomes, includ-
ing both adaptive and deleterious variants. Phylogenetic methods, applied to vari-
ant DNA sequences, are used to trace the origin and spread of pathogens such as
HIV, and have been used to identify criminals who deliberately infected victims
(such as unwanted sexual partners) with HIV [103].Using organisms’ adaptations
A great many things that humans would like to do or make have already been done
or made—by natural selection, in one or another of the millions of species, living
or extinct. Some of these adaptive characteristics are, or could be, used directly. The
antibiotic penicillin is an adaptation of the Penicillium chrysogenum fungus for sup-
pressing competing bacteria. The polymerase chain reaction (PCR) that is the foun-
dation of modern molecular biology uses the heat-stable DNA polymerase isolated
from the bacterium Thermus aquaticus, which lives in hot springs and hydrothermal
vents. The CRISPR-Cas9 mechanism, which evolved in bacteria to combat foreign
DNA such as bacteriophage, is an enormously important tool for surgically alter-
ing genes to meet our purposes. Artemisinin, a drug that suppresses malaria, was
discovered in sweet wormwood (Artemisia annua); it is one of many thousands of
compounds with antibiotic properties that plants have evolved as defenses against
herbivores and parasites. The silkworm Bombyx mori has been used for silk produc-
tion for thousands of years, and various spider silks, with diverse tensile features,
are now being studied for a range of possible industrial uses.
Other adaptations provide inspiration, or serve as models, for useful inventions,
an approach called biomimetics [106]. The inventor of Velcro was inspired by the
hooks on the burrs that have evolved for seed dispersal in many plants. Bioengi-
neers have studied the feet of geckos, which can run across ceilings and climb on
glass, as models for dry adhesion, and have found in the byssal threads of mus-
sels a chemical basis for underwater adhesion. The naked mole-rat (Heterocepha-
lus glaber; see Figure 12.10A) is exceptionally long-lived yet appears to be almost
completely free of cancer, perhaps because of its high concentration of hyaluronan,
a major component of the extracellular matrix [112]. And a recent, potentially very
important, discovery is that a bacterium that normally inhabits the human nose,
Staphylococcus lugdunensis, produces an antibiotic that kills diverse multidrug-resis-
tant pathogens, including methicillin-resistant Staphylococcus aureus (MRSA) [125].
Much of what is known about the countless adaptive characteristics of diverse
organisms has been learned by botanists, entomologists, microbiologists, and
other such experts on specific taxa, and testifies to the immense value of taxonomy
and natural history. Understanding these adaptations has often been enhanced by
evolutionary research, such as studies of form and function, of life histories, and of
coevolution of plants and herbivores.Agriculture and natural resources
The development of improved varieties of domesticated plants and animals is evo-
lution by artificial selection (see Chapter 6). Evolutionary genetics and plant and
animal breeding have had an intimate, mutually beneficial relationship for more
than a century. Theoretical evolutionary methods and experimental studies of
Drosophila and other model organisms have contributed both to traditional breed-
ing and to modern quantitative trait locus (QTL) analysis, which is used to locate
and characterize genes that contribute to traits of interest (see Chapter 6).22_EVOL4E_CH22.indd 585 3/22/17 1:49 PM