5. To relate human genetics to current issues in genetic screening, genetic counseling and genetic engineering.
6. To provide an awareness of the relationship of the individual genome to the genetic makeup of the human population and its ramifications to human diversity.
7. To provide a learning opportunity for students enrolled in Biological and Health Sciences applicable to career areas including biomedical technology, pre-medical, secondary education, special education, and nursing.
How are traits determined? Traits can be determined predominantly by one gene. Mendelian traits result from variation in alleles of one gene. Traits can be determined by multiple genes. Polygenic traits result from variation in several genes. Traits can be determined by genes and environment. Multifactorial traits result from effects of one or more genes and the environment.
Genetic Risk Absolute risk the probability that an individual will develop a condition or trait Relative risk the likelihood that an individual from one group will develop a condition in comparison to another group (usually the general population) Empiric risk risk determined by observing incidence of a trait in the population Risk factor a situation that alters incidence of a disease (or trait)
Human Genome Decoded 2001
How Genetic Diseases Differ from Other Diseases
One can predict recurrence risk in other family members
Predictive testing is possible
Different populations have different characteristic frequencies
Correction of the underlying genetic defect may be possible
Our First Assignment
Developing a family history according to recommendations of the American Society of Human Genetics.
Building a pedigree of some trait using that pedigree to consider whether it could have a genetic component.
Unaffected Male Unaffected Female Affected male Affected female Parents Offspring Pedigree Analysis
Human Pedigree Symbols
Disease No disease
Assuming pedigrees like this are available (they never are), how do you
find linked molecular markers (and clone the gene)?
Obtain polymorphic markers for loci that "span the genome"
Identify closely linked flanking markers
Narrow non-recombinant interval and test candidates for causality