The expression of certain genes in an organism can be interdependent, and this can be tested by examining their expression in a mutant background. Which of the following is true regarding the phenotype of a fushi tarazu and engrailed double mutant?

HOX genes play an important role in development, and mutations in these genes can also be responsible for other types of developmental abnormalities. Mutations in the HOXD13 gene have been linked to:

How will the expression of hunchback protein be affected during embryonic development in female fruit flies with three or four copies of the bicoid gene?

What is the phenotype of an individual that is homozygous for bicoid loss-of-function alleles?

During vulva formation in Caenorhabditis elegans, the interaction between two neighboring cells, Z1.ppp and Z4.aaa, determines which will become the gonadal anchor cell (from which the vulva forms) and which will become a precursor to the uterus. The lag-2 gene encodes the Notch signal protein, and the LIN-12 gene encodes the Notch receptor protein. By chance, one cell ends up secreting more of the LAG-2 protein than the other cell, which causes the neighboring cell to increase production of the LIN-12 protein. The expression of LIN-12 directs the selection of the uterine pathway. What will the phenotype be if both cells express excess LIN-12 protein?

Genes A, B, and C make up the majority of the homeotic gene classes that control floral development in Arabidopsis. Which of the following genes in Arabidopsis determines the distinction between sepals and petals? 

In Drosophila melanogaster, the extra sex combs (Esc) gene controls the development of sex combs in males. What happens when the extra sex combs (Esc) gene is mutated in male Drosophila flies?