Editing Quantitative trait locus (section)

===Composite interval mapping (CIM)===

In this method, one performs interval mapping using a subset of marker loci as covariates. These markers serve as proxies for other QTLs to increase the resolution of interval mapping, by accounting for linked QTLs and reducing the residual variation. The key problem with CIM concerns the choice of suitable marker loci to serve as covariates; once these have been chosen, CIM turns the model selection problem into a single-dimensional scan. The choice of marker covariates has not been solved, however. Not surprisingly, the appropriate markers are those closest to the true QTLs, and so if one could find these, the QTL mapping problem would be complete anyway.

[[Inclusive composite interval mapping]] (ICIM) has also been proposed as a potential method for QTL mapping.<ref>{{Cite journal |last1=Li |first1=Shanshan |last2=Wang |first2=Jiankang |last3=Zhang |first3=Luyan |date=2015-07-10 |title=Inclusive Composite Interval Mapping of QTL by Environment Interactions in Biparental Populations |journal=PLOS ONE |language=en |volume=10 |issue=7 |pages=e0132414 |doi=10.1371/journal.pone.0132414 |issn=1932-6203 |pmc=4498613 |pmid=26161656 |bibcode=2015PLoSO..1032414L |doi-access=free }}</ref>