Final answer:
The two major disadvantages of using recombination frequency for genetic mapping are the variance in recombination rates across different genome regions and the lack of precise physical distance provided. These can result in inaccuracies, hence it is advisable to use additional physical mapping methods.
Step-by-step explanation:
Two major disadvantages of using recombination frequency for genetic mapping are:
- Genetic maps are solely dependent on the natural process of recombination, which can vary in different genome regions. Some areas are recombination hotspots, while others exhibit low or no recombination. This inconsistency can lead to inaccuracies when estimating genetic distances based on recombination frequency alone.
- The second disadvantage is the limitation on resolution. Recombination frequencies only provide an estimation of the order and relative distances between genes or genetic markers, not their exact location or the distance in base pairs. This is significant because recombination is not always perfectly proportional to physical distance, especially over short regions of the chromosome.
To mitigate these issues, it is recommended to supplement genetic maps with physical maps, including techniques such as cytogenetic mapping, radiation hybrid mapping, and sequence mapping. These methods provide more precise physical distances between genes and are not affected by recombination frequency.