### beginning | cause | factor:

Genetic factor
* Most genetic factors affect distribution
  - cause differences
  - influence blood pressure responses
* Some genetic factors affect absorption
  - cholesterol absorption
  - color
  - hair color
* Some genetic factors associate with atherosclerosis
  - early atherosclerosis
  - contribute to characteristics
* Some genetic factors control color
  - help medical researchers
  - place an individual at greater risk for high blood pressure
  - the succeptibility of an individual to skin cancer and other health effects
* appear to determine the development of particular phenotypic features
  - explain the paler green plants
* appear to play a major role in essential hypertension
  - an important role in many cases
* are also important
  - important - borderline tends to run in families
  - more commonly present in primary generalized epilepsy than in partial epilepsy
* are responsible for only a small percentage of cases
  - the disease in a small number of families
  - significant because they effect the development of peak bone density
  - the major determinants of allergies
* can also play a role.
* contribute both to personality and to environmental exposures.
* contribute to a broad spectrum of neurological and neurobehavioral diseases
  - behavioral responses in both humans and rodents
* do play a part in many cases, as do environmental factors like drugs.
* exert a modest influence on disease expression.
* help regulate the level of homocysteine in the blood.
* increase the tendency of developing autoimmune diseases.
* influence animals
  - individual flight zone sizes between animals of the same species or breed
  - physiological measures of handling stress
  - the degree of neoteny in individuals
* make a significant contribution to the variation of obesity and hypertension.
* operate through single genes or multiple genes.
* play a major role in the development of alcoholism
  - part in prostate, colorectal and breast cancer
  - part, probably by increasing the risk of an imbalance in brain chemistry
* play a role in a small number of glaucoma cases
  - both gastric and duodenal ulcer
  - most diseases
* predispose some individuals to chronic depression.
* render some people especially vulnerable to alcohol dependence.
* underlie all aspects of health and disease.

### beginning | cause | factor:

Genetic marker
* Some genetic markers indicate increased susceptibility to xenobiotics.
* act like signposts across the chromosome.
* are DNA base sequences linked to a disease-causing gene
  - invaluable for genome mapping
  - like signposts that help researchers find their way around the DNA landscape
  - signposts on chromosomes that are created by links between genes
  - specific locations on the chromosome where there is known variability
  - useful mapping the location of genes and for doing linkage
* deteriorate with time, and become contaminated by the DNA of other species.
* provide means to examine evolution of breast cancers from precursor lesions.

Hereditary factor
* appear to play a role, but the disorder is practically never directly inherited.
* are an important factor contributing to obesity
  - important in determining peak bone mass
  - much more important than dietary factors in determining the bone mass
* can play a large role in physique.
* cause a large percentage of hearing loss in children.
* do play a role in migraine headaches.
* play a role in that physiological vulnerability.
* play an important role as well