Question

genetics

3. The figure below shows the structure of the human version of the tinman gene (NK.X2-5 is the vertebrate homologue of tinman). It also shows the mutations found in the affected families and compares the homoebox, sequence of the human gene to other similar genes. Figure 3 Structure of the human NKX2-5gene, positions of mutations, and sequence comparison to related genes. 15 KB ATG TAG PES P2AS as PSAS PAAS PIS Structure of the human NKX2-5gene, positions of mutations, and sequence comparison to related genes. (A) NKX2-5is encoded by two exons (open rectangles) separated by a 1.5-kb intron. Primer sequences are denoted and provided in (14) Mutations Gin170ter and Thr178Metaiter sequences in helix 2 of the homeodomain (dark hatching). The Gin198ter mutation terminates translation just after helix 3, thereby deleting the COOH-terminal Nk domain (clear Comparison of normal and mutant NKX2-5 sequences (21) with members and related genes:thyroid nuclearfactor-1 (TTF-1),tinman bagpipe, and antennapedia (Antp) (13,16). Gens names are prefixed with a species abbreviation in lower case: h, human: m, mouse: x, Xenopuslaevis, c, chicken, and d Drosophila Dots denote identity, letters denote amino acid differences Asterisks indicate termination signals. The Thr178Met defectalters a residue that is highly conserved in related genes. Three a helices within the homeodomain are sequences in other NK gene family indicated below the sequences Science (9 points) Is the human tinman gene (hNKX2-5) more closely related to the mouse or the xenopus NKX2-5 gene? Is the human tinman gene (hNKX2-5) more closely related to the mouse or the xenopus NKX2-3 gene? Is the human tinman gene (hNKX2-5) more closely related to the mouse NKX2-6 or the chicken NKX2-8 gene? c.

Answer 1

In the legend of figure 3, it's mentioned that Dots indicate identity with the human tinman NKX2-5 gene sequence and letters denote amino acid differences.

The human tinman gene (hNKX2-5) is more closely related to mouse (m) NKX2-5 gene then the Xenopus (x) NKX2-5 gene as there are more dots in the alignment of human and mouse gene.

The human tinman gene (hNKX2-5) is equally related to the mouse and the Xenopus NKX2-3 gene as there is a difference of 5 amino acid in both cases.

Difference between hNKX2-5 and mNKX2-6 gene is of about 13 amino acids and the difference between hNKX2-5 and cNKX2-8 gene is of about 7 amino acids. Clearly, the human tinman gene (hNKX2-5) is more closely related to chicken (c) NKX2-8 gene than mouse ( m) NKX2-6 gene.