The recombination frequency of the two gene pairs is 3%.
The number of recombinant offspring(r.o.) / total number of offspring x 100% = recombination frequency(θ):
r.o./total x 100% = θ
30/100 x 100% = 3%
Recombinant offspring are children that have a different allele combination to their parents.
For example, say a mother has a haploid cell with the alleles AB and the father has a haploid cell with the alleles ab. These combine to make a diploid cell with the sequence Aa+Bb.
Formation of Recombinant Offspring :
Recombination can happen in two different ways; independent assortment and crossing over.
- Independent assortment is when the maternal and parental DNA are mixed during meiosis, creating a new gene sequence.
- Crossing over happens during the first stage of meiosis when the two homologous chromosomes are paired and a portion breaks off on the same loci then reconnects to a different end. Crossing over can only happen when there isn't a physical linkage of the parental alleles.
Recombination frequency (θ) is the frequency with which a single chromosomal crossover will take place between two genes during meiosis. A centimorgan (cM) is a unit that describes a recombination frequency of 1%. In this way we can measure the genetic distance between two loci, based upon their recombination frequency. This is a good estimate of the real distance. Double crossovers would turn into no recombination. In this case we cannot tell if crossovers took place. If the loci we're analysing are very close (less than 7 cM) a double crossover is very unlikely. When distances become higher, the likelihood of a double crossover increases. As the likelihood of a double crossover increases we systematically underestimate the genetic distance between two loci.
When two genes are close together on the same chromosome, they do not assort independently and are said to be linked. Whereas genes located on different chromosomes assort independently and have a recombination frequency of 50%, linked genes have a recombination frequency that is less than 50%.
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Answer:
Resistance in insects develops when the same insecticide (or class of insecticides) is used against a pest population over and over again. Some insects will survive the same dose that kills their friends. Those that survive pass on that survival trait to their offspring.
Explanation:
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Answer:
both are good homes for mosquitoes
The pia mater is the only meninges to continue into a brain sulcus after the brain surface.
What are meninges?
The skull and spinal cord are encased in three tiers of membranes called meninges. These are:
- The pia mater is the fragile inner layer.
- The arachnoid, a fluid-filled web-like structure that forms the brain's intermediate layer, is what gives the brain its cushioning effect.
- The dura mater is the name of the hard outer layer.
The term for the three gaps between the meninges-
- The gaps between the layers of the meninges are known as meningeal spaces.
- Epidural, subdural, and subarachnoid are the three clinically important meningeal compartments.
The function of meninges:
- It acts as a shock absorber, the CNS (central nervous system) will shield our brain from trauma harm, such as a knock to the head.
- They secure our central nervous system and prevent our brain from shifting inside our skull.
Therefore the correct solution is an option (A),i.e., pia mater.
The complete question is:
The only one of the meninges that follows the brain surface into a cerebral sulcus is the
a. pia mater.
b. alma mater.
c. dura mater.
d. arachnoid mater.
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