Gene Mapping: Then and Now

Early Gene Mapping

The work of Thomas Hunt Morgan defined the earliest steps in mapping genes to chromosomes. Work from his lab defined the first sex-linked traits, crossing over, linkage, recombination rates and interference.

1.1

Discovery and Types of Genetic Linkage

Soon after the rediscovery of Mendel's work, several scientists noted traits in their crosses seemed “coupled.” But this deviated from Mendel's principles, so how did they explain this?

1.2

Thomas Hunt Morgan and Sex Linkage

Can paying attention establish a new field? Learn about Thomas Hunt Morgan, the first person to definitively link trait inheritance to a specific chromosome and his white-eyed flies.

1.3

Thomas Hunt Morgan, Genetic Recombination, and Gene Mapping

How would you feel if you had to be the one to challenge Gregor Mendel's paradigm-shifting laws of inheritance? Yet Thomas Hunt Morgan did exactly this and in the process made gene mapping possible.

Unit 2

Mapping in Model Organisms

Model organisms are valuable for the search of the genes that are responsible for specific phenotypes. Genomic sequence can help scientists locate candidate genes more rapidly. Often screens are used to find novel candidates for specific phenotypes.

2.1

C. elegans: Model Organism in the Discovery of PKD

What does the sex of worms have to do with human kidneys? See how C. elegans research has unlocked scientists' understanding of polycystic kidney disease.

2.2

Leader of the pack: gene mapping in dogs and other model organisms

The domestic dog offers a unique opportunity to explore the genetic basis of disease, morphology and behaviour. We share many diseases with our canine companions, including cancer, diabetes and epilepsy, making the dog an ideal model organism for comparative disease genetics. Using newly developed resources, whole-genome association in dog breeds is proving to be exceptionally powerful. Here, we review the different trait-mapping strategies, some key biological findings emerging from recent studies and the implications for human health. We also discuss the development of similar resources for other vertebrate organisms.

2.3

Mapping Genes to Chromosomes: Linkage and Genetic Screens

After the invention of whole-genome sequencing, we now know the sequences that make up an entire organism. Now what do they mean? To answer that, we turn back to linkage mapping in model organisms.

Unit 3

Mapping in Humans

Mapping genes in humans is often complicated by the complex nature of most phenotypes. Mapping disease and quantitative trait loci is a major endeavor of many human geneticists.

3.1

Gene Mapping and Disease

What's the easiest way a researcher can perform a linkage analysis and map genes to chromosomes? By using his own family's blood! See how Roger Donahue mapped the first gene to an autosome.

3.2

Polygenic Inheritance and Gene Mapping

Ever griped about your height? Figuring out its origins hasn't been any easier for geneticists who are turning to high-throughput, genome-wide association studies for clues.

3.3

Chromosome Mapping: Idiograms

How do scientists find their way around a chromosome? With chromosome maps called idiograms, researchers can pinpoint the locations of genes and locate abnormal gene forms.

3.4

Rare Genetic Disorders: Learning About Genetic Disease Through Gene Mapping, SNPs, and Microarray Data

Most diseases are caused by mutations in more than one gene. So what clues can monogenic, or single-gene disorders provide?

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