The Afrikaner population of South Africa is mainly descended from one shipload of
immigrants which landed in 1652. The early colonists included individuals with a
number of rare genes. The ship of 1652 contained a Dutch man carrying the gene for
Huntington's disease, an autosomal dominant disease which does not appear until the
sufferer is over 40 years old and leads to certain death within five to 10 years. Today,
the Afrikaner population has an unusually high frequency of the gene that causes
Huntington's disease, because those original Dutch colonists just happened to carry
that gene with unusually high frequency.
anism of evolution is this?
Reproductive isolation
Founders effect
Co evolution
Bottle neck

Astudent from one of the research labs is having trouble preparing a slide for examination and photographing. the bacterial slide that he has brought to you was prepared using a commercially purchased stain. he has asked for your in determining what he is doing wrong so that he can change the lab protocols and continue on with his project. after examining the slide under oil immersion, you determine that no bacteria are present even though the student is able to show you the culture he used to make that slide that has visible growth in the liquid medium. which of the following statements does not explain the fact that there are no bacteria present on the student’s slide? by not allowing a glass slide to completely air dry before heat fixation, the flame will cause the surrounding water to boil and this will damage the bacterial cell. overheating during the fixation step boiled the water within the bacterial cells and resulted in the cells bursting. insufficient heating of the slide did not drive out the thin layer of water and this resulted in minimal bonding between the bacteria and the glass slide. rinsing with alcohol during the washing step stripped the bacteria off the glass slide. rinsing with alcohol during the washing step stripped the bacteria off the glass slide.