Answer:
A. I, II, III, and V only
Explanation:
In genetics, an allele refers to the specific form of a gene, which encodes traits. These alleles are usually in pairs in a diploid organism i.e. an organism with two sets of chromosomes. According to Gregor Mendel,
- An allele can either be DOMINANT when the allele masks the phenotypic expression of its allelic pair while the allele that is masked is said to be RECESSIVE.
- Two alleles can also be CO-DOMINANT when the two alleles are neither dominant or recessive over one another but are simultaneously expressed in that particular gene.
- Alleles can also be INCOMPLETELY DOMINANT when one allele is not completely dominant over the other, hence, forms a third intermediate phenotype when in combination with the second allele i.e. in an heterozygous state.
Based on this, an allele can be dominant (I), recessive (II), codominant (III), and incompletely dominant (V).
Answer:
Bridgham et al. (2006) showed that the interaction between a steroid hormone (aldosterone-M) and its receptor (mineralocorticoid) evolved by Darwinian gradualism. In this work, the authors demonstrated a primitive affinity between the hormone and its receptor that was initially present in chemically similar but more ancient ligands. This result has implications in understanding the association between gene duplication and the evolution of hormone signaling pathways. For example, in invertebrates, this work reinforces the importance of gene duplication in the existing interaction between paralogous glucocorticoid receptors and their receptor mineralocorticoid genes that were derived from duplication (Thornton 2001).
The publications above cited are the following:
J.T. Bridgham, S.M. Carroll, and J.W. Thornton (2006). Evolution of hormone-receptor complexity by molecular exploitation. Science, 312(5770), 97-101.
JW Thornton. Evolution of vertebrate steroid receptors from an ancestral estrogen receptor by ligand exploitation and serial genome expansions, Proc Natl Acad Sci USA (PNAS), 2001, vol. 98 10 (pg. 5671-5676).
Answer: true
Explanation: In gel electrophoresis, the smaller the size/molecular weight of DNA the faster it moves across the gel and vise versa. This is as a result of the pore size of the gel which is usually prepared 1g of agarose in 100ml of distilled water. So a DNA fragment with 1000 base pairs will "struggle" its movement across the gel pore making it mive less faster and further. Movement and molecular weight of DNA are inversely proportional.
The correct answer is allele.
I hope I helped!