What phenotypic ratio would you expect as a result of a test cross between a dihybrid organism and one that is homozygous recessive for alleles at two independent loci?
a. 3:1
b. 9:3:3:1
c. 1:1:1:1
d. 1:2:1
e. 9:4:2:1
Answer:
c. 1:1:1:1
Explanation:
When a heterozygous individual for two genes is test crossed with a double homozygous recessive individual, the progeny is obtained in 1:1:1:1 phenotypic ratio. This occurs as the heterozygous dominant individual forms four types of gametes in 1:1:1:1 ratio while the homozygous recessive individual would form only one type of gamete having one recessive allele for each gene.
For example, a test cross between TtRr (tall and red) and ttrr (short and white) would produce a progeny in following ratio=
1 tall, red: 1 tall, white: 1 short, red: 1 short, white
Here, T= tall, t= short, R= red, r= white
an element on the periodic table
Answer:
Denaturation process: The DNA template
Annealing process: Primers
Elongation process: dNTPs and Taq polymerase
Explanation:
For the denaturing process, the only ingredient that is required is the DNA template that will be separated from a double helix (or double strand) into a single strand, by increasing the temperature to 95 C, (at this temperature the hydrogen bonds that keep together the double stranded break). After the double strand is denatured, the following process is annealing. For this, the required ingredient are the primers; these primers will hybridize or anneal according to the nucleotide complementarity to the single strand of the DNA. Finally, for the Elongation process, you will require the Taq polymerase and the dNTPs. The enzyme will synthesize or “generate” a new strand of DNA based on the DNA template, using the provided dNTPs in the direction 5’ to 3’.
I hope this clarify you inquiry.
