Linkage refers to the tendency of inhertance of the DNA sequences that are close together on a chromosome during the meiosis of sexual reproduction. It can be measured by the recombination frequency.
Recombination frequency describes the proportion of recombinant offsrpring produced in a genetic cross between two organisms. It is the frequency with which a single chromosomal cross over takesplace between two genes during the process of meiosis. Recombination frequency (RF) is given by
RF= Recombinants /total offspring x 100.
In the above example, the number of recombinant offspring is 20 and the total offspring is 400. By substituting these values,
RF= 20/400 x100
= 5.
The recombination frequency for the above cross is 5.
Answer:
e) directional selection
Explanation:
Directional Selection:
- The type of natural selection that favors one of the extremes of the phenotype spectrum, shifting the allele frequency to one direction
- This type of selection selects against intermediate and one of the extreme phenotypes.
- In this particular case, the increasing pollution has pushed the plants to evolve better acid tolerance.
- This indicates that if the environmental conditions worsen, only the acid tolerant plants will be able to survive.
* Another example is illustrated in the image. The graph shows the shifts in allele frequency.
Antibiotics killed bad bacteria . that means white blood cell resistant bacteria
Answer:
b.gibberellins is the correct answer.
Explanation:
Gibberellins are the plant growth hormones that are used to stimulate seed germination and elongation.
When gibberellins are sprayed in sugarcane crops it increases the sugar cane length, growth, and production.
Gibberellins are found in plant tissues such as flowers, shoots, and fresh leaves.
Gibberellic acid is used in horticulture/agriculture to increase the yields of crops.