Avbildningsmarkörer

Avbildningsmarkörer are specific genetic or phenotypic markers used to construct genetic linkage maps of organisms. The term originates from Swedish, where “avbildning” means mapping and “markör” means marker. These markers help researchers determine the relative positions of genes on chromosomes by identifying recombination frequencies between co‑herited loci.

In plant genetics, avbildningsmarkörer have played a pivotal role in breeding programs. Simple Sequence Repeats (SSRs), known as microsatellites, and Single Nucleotide Polymorphisms (SNPs) are among the most common types. SSRs produce varying repeat lengths that can be distinguished by gel electrophoresis or capillary sequencing, while SNPs are detected by PCR‑based assays or next‑generation sequencing. The high polymorphism and abundance of SSRs make them valuable for mapping in species with limited genomic resources, whereas SNPs offer higher throughput and lower cost for species with sequenced genomes.

Avbildningsmarkörer are also employed in quantitative trait loci (QTL) mapping, where they serve as anchors to identify genomic regions controlling complex traits such as yield, disease resistance, or drought tolerance. In addition, they support marker‑assisted selection, enabling breeders to accelerate genetic gain by selecting individuals carrying desirable alleles at mapped loci.

Historically, avbildningsmarkörer have evolved alongside advances in molecular biology. Early mapping methods relied on Restriction Fragment Length Polymorphisms (RFLPs), which were later supplanted by SSRs and now largely replaced by SNP arrays and genotyping‑by‑sequencing approaches. This progression has drastically increased marker density, enhancing map resolution and the precision of trait locus identification.

Overall, avbildningsmarkörer constitute an essential toolkit in modern genetics, enabling detailed exploration of genome structure, function, and evolution.