Platyfish with spots have an x-linked gene that produces the spots. all platyfish have an autosomal repressor that inhibits the expression of the spot-producing gene. the closely related swordtail lacks both the spot-producing gene and the repressor. in backcrosses between these two species, some hybrids receive the spot-producing gene, but not the repressor. these individuals can develop malignant tumors, because the expression of the spot-producing gene is not properly regulated. this appears to be an example of:

It has been said that veterinarians are the world's best doctors, since their patients cannot tell them what is wrong. what are some of the differences between human and animal medicine? what are the advantages and disadvantages of each?

What causes the phospholipids to organize themselves the way they do

Examine the two squirrel populations in the accompanying figure. the populations are separated by a geographic barrier. if after a long period of time the two species are no longer separated, what evidence is needed to determine if speciation has occurred? the figure shows two populations of squirrels separated by a geographic barrier. examine the two squirrel populations in the accompanying figure. the populations are separated by a geographic barrier. if after a long period of time the two species are no longer separated, what evidence is needed to determine if speciation has occurred? the figure shows two populations of squirrels separated by a geographic barrier. polyploidy is creating new species. the two populations are not interbreeding freely. hybrid offspring of the two populations begin to appear. one species will increase into a population size twice as large as the other species.