Many traits of economic or medical significance are determined by quantitative trait loci (QTLs) in which many genes, usually scattered throughout the genome, contribute to expression.

What is meant by the term cosegregate in the context of QTL mapping? Why are markers such as RFLPs, SNPs, and microsatellites often used in QTL mapping?

Key Concepts

Cosegregation

Cosegregation refers to the phenomenon where two or more genetic markers are inherited together more often than would be expected by chance. In the context of QTL mapping, it indicates that a specific marker is linked to a trait of interest, allowing researchers to track the inheritance of traits alongside these markers. This is crucial for identifying the genetic basis of quantitative traits.

Quantitative Trait Loci (QTL)

Quantitative Trait Loci (QTL) are regions of the genome that are associated with the variation in a quantitative trait, which is typically influenced by multiple genes. QTL mapping helps identify these regions by correlating phenotypic data with genetic markers, enabling researchers to understand the genetic architecture of complex traits, such as height or disease susceptibility.

Genetic Markers

Genetic markers, such as RFLPs (Restriction Fragment Length Polymorphisms), SNPs (Single Nucleotide Polymorphisms), and microsatellites, are specific sequences in the genome that can be used to identify individuals or species. In QTL mapping, these markers serve as reference points to track the inheritance of traits and help in locating QTLs by providing a means to analyze genetic variation and linkage to phenotypic traits.