ở ruồi giấm gen a quy định cánh dài trội hoàn toàn so với gen a quy định cánh ngắn cho ruồi giấm cánh dài và cánh ngắn giao phối với nhau f1 tỉ lệ 50% ruồi cánh dài 50% ruồi cánh ngắn tiếp tục cho f1 giao phối với nhau thì f2 thống kê ở cả quần thể có tỉ lệ 9 cánh dài 7 cánh ngắn

The gene that causes sickle-cell disease is present in a higher percentage of residents of sub-saharan africa than among those of african descent living in the united states. even though this gene causes sickle-cell disease, it also provides some protection from malaria, a serious disease that is widespread in sub-saharan africa but absent in the united states. discuss an evolutionary process that could account for the different percentages of the sickle-cell gene among residents of the two regions.

The hematodinium parasite becomes less of a problem for the blue crab when the crab is very young. fishing is thriving in the region. the crab moves to less salty water. a significant percentage of the population is impacted.

Where does the information about where each transcription factor binds originate?