Question

Directions: Look at the following amino-acid sequences from two warm-water species and one cold-water species and identify where changes in the sequence occurred. Please go from cold to warm. Going the opposite direction will result in the wrong answer.Line 1: C. punctipinnis: Temperate (cold-adapted)Line 2: C. caudalis: Tropical (warm-adapted)Line 3: C. xanthochira: Tropical (warm-adapted)151…GFERHRVIGS GTNLDSARFR HIMGEKLHLH PSSCHGWIVG EHDGSSVPVWGFERHRVIGS GTNLDSARFR HIMGEKLHLH PSSCHGWIVG EHDGSSVPVWGFERHRVIGS GTNLDSARFR HIMGEKLHLH PSSCHGWIIG EHDGSSVPVW201…SGVNVAGVSL QGLNPQMGTD GDSEKWKEVH KLVVDGAYEV IKLKGYTSWASGVNVAGVSL QALNPQMGAE GDSENWKAVH KQVVDGAYEV IKLKGYTSWASGVNVAGVSL QGLNPKMGAE GDSENWKEVH KLVVDGAYEV IKLKGYTSWA251…IGMSVADLVE SIMKNLHKVH PVSTLVQGMH GVKDEVFLSV PCVLGNSGLTIGMSVADLVE SIMKNLHKVH PVSTLVQGMH GVKDEVFLSV PCVLGNSGLTIGMSVADLVE SIMKNLHKVH PVSTLVQGMH GVKDEVFLSV PCVLGNSGLT301…DVIHMTLKPE EEKQLVKSAE TLWGVQKELT DVIHMTLKPD EEKVLVKSAE TLWGVQKELT DVIHMTLKPD EEKQLVKSAE TLWGVQKELTNote that the highlighted mutation is spot 189. Please count all the way. Row numbers are the wrong answer!2. What were the changes in the chemical properties of the R-groups? Use the amino-acid chart to in the Powerpoint file to answer this question.Example: Both valine and isoleucine are nonpolar.1) _______________________________________________________________2) _______________________________________________________________3) _______________________________________________________________4) _______________________________________________________________

Answer 1

To answer this question we have to consider the aminoacidic sequences the exercise gives to us for three different species of marine fishes: Chromis punctipinnis, C. caudalis, and C. xanthochira, which are adapted to different conditions, being the first one adapted to cold temperatures, and the two latter adapted to warm conditions.

The exercise shows us four sequences where there're genetic variations in terms of aminoacidic sequences: the first one is shown below the number 151, where instead of Valine (V), the third species has Isoleucine (I), as indicated with the vertical rectangle.

Below the number 201 we can see multiple variations between the three species, where, in the second set of amino acids, a Valine (V) is replaced by an Alanine (A) in the second fish species.

While in the third set of amino acids, a Glutamate (E) by an Alanine (A) in the second fish species too.

Below the number 301, there's a Glutamate (E) that is replaced by an Aspartate (D).

We know then that there were at least four replacements, and considering the information from the chart of amino acids, we can say the following:

1. Valine changed for Isoleucine: there was not a change in the chemical properties, because both amino acids have non-polar chains

2. Valine changed for Alanine: there was not a change in the chemical properties, because both amino acids have non-polar chains

3. Glutamate changed for Alanine: there was a change because the aminoacidic chain lost their electronegativity

4. Glutamate changed for Aspartate: there was not a change because the aminoacidic chain kept it's electronegativity.