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:
When diverse molecules and objects are brought together, they generate a chemical, which causes sickness. Forest fires can occur spontaneously or as a result of human activity. Natural factors include severe droughts and a lack of precipitation. Campfires or the usage of a flare gun can be used to create man-made causes.
<span> Biotic components or biotic factors are any living organisms that affect another
organism. These components shape an ecosystem which includes animals that
consume organisms in question and its living food that the said organisms
consume. Biotic components include human influence. Producers, consumers and
decomposers usually comprise biotic components.</span>
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