QUESTION 3 Casein is the major food protein found in mammalian milk, and its ami

Question

QUESTION 3 Casein is the major food protein found in mammalian milk, and its amino acid sequence is very similar to a group of proteins called SPARCS found in both vertebrates and invertebrates. Both SPARCs and casein bind to calcium ions, and are involved in bone deposition in all bony animals, including non-mammals like fish. The tree above shows the relationships of three SPARC family proteins based on amino acid similarity. Referring to the tree, which of the following statements about the evolution of casein is most correct: worm cow cOW SPARC SPARCCasein A duplication of the SPARC-encoding gene resulted in a new gene that evolved a different function in early mammals b. Non-mammals lost the casein-encoding gene that they inherited from the last common ancestor of animals There are only so many ways a protein can bind calcium ions, so the sequence match is due to convergence. d A mutation in the SPARC-encoding gene resulted in the evolution of a new protein with a different function O c.

Explanation / Answer

option a is more appropriate then any other options.

in the process of evolution we can say that is SPARC coding gene is duplicated and undergo some changes which leads to formation of cow casein protein.

option second is not valid because orientation of these genes are not given correctly.

There are various different methods formethods for binding proteins to calcium ion and they may or may not be involved in the same regions.

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