Experimental technique: the use of parabiosis to evaluate hormone functioncoleman and his colleagues used a technique called parabiosis to evaluate if the products of the ob and db genes were involved in hormonal regulation of appetite and body fat. in parabiosis, two closely related animals are surgically joined from the shoulder to the pelvis. new capillaries grow between the two organisms, resulting in a shared circulatory system. however, not all compounds that circulate in the blood are exchanged between the two individuals. long-lived (slowly metabolized) compounds such as hormones are exchanged. short-lived (rapidly metabolized) compounds such as glucose and fatty acids are not exchanged. consider a db/db mutant and a wild-type mouse that will be joined by parabiosis. the db/db mutant has greatly elevated levels of both appetite-suppressing hormone and glucose because of its inability to suppress its appetite. in contrast, the wild-type mouse has normal levels of both hormone and glucose.

The tasmanian devil, a marsupial carnivore, is facing extinction due to devil facial tumor disease (dftd) which causes bulging cancerous lumps and lesions to erupt around the face and neck — often causing enough deformation to make seeing or eating difficult. dftd has evolved into a contagious cancer, a trait that is unique among cancers. devil mating behavior involves biting around the head and neck, allowing cells from one individual — especially cells from the crumbly dftd tumors — to be transferred to the wounds or face of a new individual. this marsupial was once found across australia, but sea levels rose, isolating the tasmanian population, while the australian population went extinct. what would be an outcome of genetic isolation that is likely to have impacted the spread of dftd? a) reduced territory puts diseased individuals in greater contact with non-diseased ones. b) inbreeding results in less variation in facial features so the cancer is generally fatal. c) genetic isolation has made it difficult for scientists to develop a vaccine against dftd. d) the lack of genetic variation in the immune system of tasmanian devils minimizes resistance to the disease.

What materials must dams have to produce electricity, and what must occur?

Urgent in guinea pigs, black fur (b) is dominant over white fur (b). cross a heterozygous (hybrid) black guinea pig with a homozygous (purebred) white guinea pig. complete a punnett square, identify the genotype(s), phenotype(s), and probability (% and fraction) that the offspring will be black and white?