151. A marker present outside the targeted QTL used to check the crossing over is called:
1. Peak marker
2. Background marker
3. Recombinant marker
4. Foreground marker

Question

A marker present outside the targeted QTL used to check the crossing over is called:

1. Peak marker

2. Background marker

3. Recombinant marker

4. Foreground marker

Detailed Explanation

In genetic mapping and Quantitative Trait Locus (QTL) studies, different types of markers are employed to analyze the genetic relationships between various traits and the genes responsible for them. These markers are used to track the inheritance of genetic traits and to understand how genes interact with one another. In the context of QTL mapping, understanding the role of each type of marker is crucial for accurate genetic analysis.

Types of Markers in QTL Studies

1. Peak Marker:

   • The peak marker refers to a marker that is located very close to the targeted QTL and is typically used to identify regions associated with the trait of interest. It does not refer to a marker used for checking crossing over.

2. Background Marker:

   • The background marker is a marker that is present outside the targeted QTL region. It is crucial for tracking crossing over events between the regions that are distant from the QTL. The purpose of this marker is to ensure that any recombination occurring in the study is monitored, and it helps to verify that the observed inheritance pattern is truly due to the QTL rather than unrelated loci.

3. Recombinant Marker:

   • A recombinant marker is used to detect the occurrence of recombination during the process of meiosis. While these markers are critical for identifying crossovers, the term does not specifically refer to the marker outside the targeted QTL. Rather, it’s focused on detecting recombination events.

4. Foreground Marker:

   • The foreground marker is located within the region of the QTL of interest. It is used to directly monitor the inheritance of alleles related to the trait being studied. It helps in detecting the genetic variation that is linked to the phenotype.

Correct Answer and Explanation

The correct answer is:

2. Background Marker

This is because the background marker is located outside the targeted QTL region. It helps in checking crossing over events and provides information about recombination between the QTL and other loci, ensuring that the genetic study results are valid and the QTL’s effects are accurately mapped.

Conclusion

In QTL mapping, background markers play an essential role in validating the results of genetic studies by monitoring crossing over events. These markers, located outside the QTL region, help in distinguishing recombination that is associated with the QTL from other genetic variations that might affect the trait. Proper understanding and use of these markers are key to successful genetic analysis and accurate trait mapping.