In cucumbers, heart-shaped leaves (h) are recessive to normal leaves (h) and having numerous fruit spines (n) is recessive to having few fruit spines (n). the genes for leaf shape and number of spines are located on the same chromosome; findings from mapping experiments indicate that they are 32.6 m. u. apart. a cucumber plant having heart-shaped leaves and numerous spines is crossed with a plant that is homozygous for normal leaves and few spines. the f1 progeny are then crossed with plants that have heart-shaped leaves and numerous spines (testcross). 5a. create a drawing to indicate the chromosomes, gene arrangements and phenotypes of the f1 parents and the nonrecombinant and recombinant progeny produced from the testcross. (8 points)

Over the past 60 years, many amphibian species have experienced significant population declines and some species have become extinct. scientists suspected that local human activities such as the destruction of wetlands, regional pollution, and deforestation were the main reasons for these losses. however, research over the past 20 years reveals significant amphibian population declines in protected areas of the world, such as nature preserves and parks. these global declines suggest widespread problems including increased ultraviolet radiation, acid rain, and disease. in switzerland, for example, 14 of the 20 native amphibian species are threatened with extinction. chytridiomycosis is a fungal disease first identified in 1998 as a cause of massive amphibian deaths. in some severely impacted populations, a few individuals have survived, perhaps because of some natural resistance. if these resistant individuals continue to survive and prosper, new resistant populations might emerge. this would be an example of the founder effect artificial selection genetic drift natural selection sexual selection

As a small change in a person's dna can cause a genetic disorder

What must be done to breed dogs for a partical trait