The recombination frequency between two genes is always less than 50% because the two genes are on different chromosomes, which is why chromosomes are only passed down the female line.
If two genes are on the same chromosome, then there is a 50% chance that the recombination frequency between the genes will be equal to 100%.
The answer is discussed here about which statement explains why the recombination frequency between two genes is always less than 50%?
Since chromosomes are only passed down the female line, recombination frequency between two genes must be less than 50%.
However, if two genes are on the same chromosome, then there is a 50% chance that the recombination frequency will be equal to 100%. This is why geneticists have found it difficult to map out specific genes to certain traits.
Here are some points discussed about why the recombination frequency between two genes is always less than 50%-
1. Different chromosomes.
If the two genes are on different chromosomes, then recombination frequency between two genes is always less than 50% because chromosomes are only passed down the female line.
However, if the two genes are on the same chromosome, then there is a 50% chance that the recombination frequency will be equal to 100%, and this is why geneticists have found it difficult to map out specific genes to certain traits.
2. Bigger populations.
Using gene mapping and breeding of populations, geneticists have detected that some traits do not cause any problem in males but may cause some problems for females or even both male and female species.
This is because most of the time, the genes that cause the traits may be on another chromosome and cannot be identified.
3. Gene mapping and breeding in species and populations.
Gene mapping and breeding is vital for genetic research, especially in species and populations with bigger populations such as rats.
This process can be done easily using traditional methods with bigger populations because it is easier to identify the trait related genes by analyzing generations of families (where traits are passed down generations).
Or by observing how certain organisms with specific traits survive in habitats (in order to determine how the organisms’ body structure enables them to survive).
These methods allow geneticists to easily determine which chromosomes contain which genes.
4. Incorrect mapping of chromosomes.
Many geneticists believe it is difficult to map out specific genes to certain traits because the chromosome looks like spaghetti, which makes it difficult for geneticists to identify specific traits. However, this is not entirely true.
An example that shows why geneticists cannot easily identify specific genes is the case of the chicken (Gallus gallus). The chicken’s physical appearance may look like typical domesticated mammals but it has traits typical of other birds.
The main problem in mapping out specific genes in this case is that geneticists do not know exactly where the chromosomes are located because they look like spaghetti while actual chromosomes can be seen in chicken embryos when they are developing.
5. Unstable DNA structures.
The genetic structure of DNA may cause problems when trying to map out specific genes because it is not stable, which means that some genes are more likely to be duplicated while others are more likely to be destroyed.
This is the reason why it has been difficult for geneticists to identify specific genes in animal species that have not been domesticated because the chromosome structure of these animals is unstable.
However, after domestication, the chromosome structure becomes stable and this is why geneticists have found it easier to identify these traits in certain species.
6. Restrictions of gene mapping and breeding techniques.
Geneticists use various techniques to identify specific genes, including gene mapping and breeding. These techniques only work well for species that have bigger populations.
They are also useful tools in species where physical traits are dominant over other traits. This is because the breeding technique works by identifying organisms with certain traits, which helps geneticists to determine which chromosomes contain which genes.
7. Different organisms have different habitats/resources.
They rely on it for survival, so their physical attributes are also different. For example, different habitats require different types of gene mapping and breeding in order to identify specific genes that are important for survival.
For instance, geneticists try to identify the genes that enable dogs (Canis lupus familiaris) to adapt to different environments in order for them to become suitable pets.
They will find it difficult because dogs need suitable habitat for hunting, which is why dog breeds do not have any of the traits associated with domestication.