A common agricultural practice is to plant the crops at high density for the ease of irrigation and harvesting. Therefore, reduced branching is a desirable trait during artificial selection. Is artificial selection more likely to favor the BRC1 allele with a low expression level? Why or why not?

Successive rounds of artificial selection should lead to a high expression of the BRC1 gene.  

Explanation:

The BRC1 (BRANCHED 1) gene is a major transcription factor belonging to the TCP family, whose name is due to the first three members characterized in this family (BRC1/TB1/FC1). In Arabidopsis thaliana, the BRC1 gene controls the expression of many genes and thus plays a key role in the plant's architecture. Mutations of this gene exhibit an altered branching phenotype when plants are compared to the wild type. Arabidopsis contains two BRANCHED genes, BRC1 and BRC2, which negatively modulate the branching process. Moreover, in maize, the overexpression of the Teosinte Branched 1 (TB1) gene has been involved in the domestication process from wild teosinte.