This chapter explores the underpinnings for observational and experimental genetics. Concepts ranging from laws of Mendelian inheritance through molecular and chromosomal aspects of deoxyribonucleic acid (DNA) structure and function are defined; their ultimate utilization in linkage mapping of simple Mendelian disease and common and genetically complex disease is presented. The chapter conclude...

Genomic research has two quite distinct faces. On the one hand, it produces large, curated, reference data sets through numerous networks of investigators for community use—although this aspect has great and widespread utility, it does not inspire per se. On the other hand, it allows an unbiased genome-wide view that is exciting precisely because it habitually uncovers biology that we were hope...

The phrase "mendelian randomization" has become associated with the use of genetic polymorphisms to uncover causal relationships between phenotypic variables. The statistical methods useful in mendelian randomization are known as instrumental variable techniques. We present an approach to instrumental variable estimation that is useful in family data and is robust to the use of weak instruments...

A small minority of colorectal cancers (CRCs) (≤5%) are caused by a single, inherited faulty gene. These diseases, the Mendelian colorectal cancer (CRC) syndromes, have been central to our understanding of colorectal carcinogenesis in general. Most of the approximately 13 high-penetrance genes that predispose to CRC primarily predispose to colorectal polyps, and each gene is associated with a s...

Quantitative trait locus (QTL) mapping is usually performed using markers that follow a Mendelian segregation ratio. We developed a new method of QTL mapping that can use markers with segregation distortion (non-Mendelian markers). An EM (expectation-maximization) algorithm is used to estimate QTL and SDL (segregation distortion loci) parameters. The joint analysis of QTL and SDL is particularl...

We have learned that low-density lipoprotein (LDL) cholesterol is the cause of atherosclerosis from various aspects, including a single case with familial hypercholesterolemia, other cases with different types of Mendelian dyslipidemias, large-scale randomized controlled trials using LDL cholesterol lowering therapies, and Mendelian randomization studies using common as well as rare variants as...

In epidemiological research, the causal effect of a modifiable phenotype or exposure on a disease is often of public health interest. Randomized controlled trials to investigate this effect are not always possible and inferences based on observational data can be confounded. However, if we know of a gene closely linked to the phenotype without direct effect on the disease, it can often be reaso...

A phenotypic segregation of kanamycin resistance conferred by nosnptII was investigated in two groups of transgenic cucumber lines one containing the PR-2duidA-nosnptII construct and the other with the thaumatinII-nosnptII construct to the third and fifth generation, respectively. Expression of the nptII gene was more stable and predictable in the progeny of the PR-2d lines than that of thaumat...

Mendelian genetic tools have extensively been used to improve the description of the pharmacological mechanisms involved in learning and memory. The first part of this short review describes experiments involving the bidirectional selection of rats or mice for extreme behavioral characteristics or for sensitivity to pharmacological treatments. The second part focuses specifically on in-breeding...