1) (5 point question) Monkey\'s (new world) and primates (old world) have distin
ID: 205153 • Letter: 1
Question
1) (5 point question) Monkey's (new world) and primates (old world) have distinctly different vision. Most monkey's have dichromatic vision, while primates have trichromatic vision A) (2 points) What kind of mutation occurred in the primate lineage to allow the primates to have an extra opsin gene. B) (3 points) A recent discovery determined that the howler monkey has both L and M opsins on their X-chromosome similar to primates. Look at the diagram below that depicts the opsin locus on the x-chromosome of the howler monkey. How does this differ from the primate locus, and what might explain this difference? b Howler monkeys on LCR-on LCR https://www.researchgate.net/publication/280566766_Polymorphic Color Vision_in Pri mates-Evolutionary-ConsiderationsExplanation / Answer
1)
Trichromatic colour vision depends on the presence of three types of cone photopigment. Trichromatic vision is found in all Old World monkeys, apes and humans. But in but in New World monkeys, colour vision is polymorphic. The difference in colour vision between these New and Old World primates is due to the different arrangements of the pigment genes on the X chromosome.In Old World primates, two or more X-chromosome pigment genes and an autosomal pigment gene encode the three photopigments required for routine trichromatic colour vision. While the new World monkeys typically have only one X-chromosome pigment gene; multiple alleles allow different types of dichromatic colour vision and, in females heterozygous at this locus, variant forms of trichromatic colour vision. Research suggests that the evolution of a trichromatic trait may have become fixed in old world monkey species because it provides an advantage in detecting ripe fruit in trees.
A)
In monkeys, the SWS opsin gene is located on chromosome 7, an autosome. The MWS and LWS opsin genes are located on the X-chromosome. In many primate species there are many non-functional copies of the MWS gene found on the X-chromosome. This implies that there were duplication events of the MWS gene that occurred many times throughout the history of trichtomat monkey species. One of those MWS copies accumulated a few specific DNA nucleotide substitution mutations, which gave rise to an LWS opsin gene that encoded a functional LWS opsin protein. In fact, only three specific mutations were needed over tens of millions of years in order for a functional LWS gene to successfully evolve.
B)
In howler monkeys, LCR is duplicated together with the opsin gene and is adjacent to both L and M opsin genes. With lack of some regulatory mechanism, both L and M opsin genes are expressed from the same chromosome by the interaction with their LCRs in a given M/LWS cone. While in primates, the locus control region (LCR) interacts with either the uppermost (typically L) or the second (typically M) opsin gene in an M/LWS gene array on an X chromosome, turning on the expression of the associated opsin gene
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.