[citation needed] Various phylogenetic trees for vertebrates have been constructed using comparative proteomics, genetics, genomics as well as the geochemical and fossil record.
[citation needed] Recently, genomic data has been added to techniques to make close comparisons between species and determine relatedness.
[6] With so much of the genome conserved across species, it is relatively impressive that the differences between humans and mice can be accounted for in approximately six thousand genes (of ~30,000 total).
[citation needed] Animal models serving in research may have an existing, inbred or induced disease or injury that is similar to a human condition.
These refer to models of disease that resemble human conditions in phenotype or response to treatment but are induced artificially in the laboratory.
Some examples include: Spontaneous models refer to diseases that are analogous to human conditions that occur naturally in the animal being studied.
For instance, behavioral analogues of anxiety or pain in laboratory animals can be used to screen and test new drugs for the treatment of these conditions in humans.
A 2000 study found that animal models concorded (coincided on true positives and false negatives) with human toxicity in 71% of cases, with 63% for nonrodents alone and 43% for rodents alone.
These include "1) appropriateness as an analog, 2) transferability of information, 3) genetic uniformity of organisms, where applicable, 4) background knowledge of biological properties, 5) cost and availability, 6) generalizability of the results, 7) ease of and adaptability to experimental manipulation, 8) ecological consequences, and 9) ethical implications.
Animals lack self-consciousness, self-reflection and consideration;[citation needed] moreover, hallmarks of the disorder such as depressed mood, low self-esteem or suicidality are hardly accessible in non-humans.
[citation needed] Many animal models serving as test subjects in biomedical research, such as rats and mice, may be selectively sedentary, obese and glucose intolerant.
At each site, OLAW guidelines and standards are upheld by a local review board called the Institutional Animal Care and Use Committee (IACUC).
[29] Refinement refers to efforts to make experimental design as painless and efficient as possible in order to minimize the suffering of each animal subject.
[citation needed] One aspect of this debate; however, continues to be difficult to resolve: the classification of animals according to a hierarchy, which protects some species more than others.
Because chimpanzees and other non-human primates can demonstrate intelligence, and social structure that they have a life experiences that is more cognitively complex than lower species.
Ultimately, this is an argument not likely to be resolved, however most people are more comfortable with the idea of experimentation that involves worms or flies than mice, dogs, or monkeys.
[citation needed] Ethical concerns, as well as the cost, maintenance and relative inefficiency of animal research has encouraged development of alternative methods for the study of disease.