Question

scientists know that organisms that are more closely related will have dna sequences more similar to each other than organisms that are distantly related. which two organisms below would most likely have the fewest similar nucleotide sequences in a given gene?
o a. orangutan and howler monkey
o b. scorpion and tarantula
o c. lion and horse
o d. alligator and earthworm

Explanation:

• 短吻鳄（alligator）属于爬行纲，蚯蚓（earthworm）属于环节动物门，二者亲缘关系最远，其特定基因的核苷酸序列相似度最低。
• 猩猩（orangutan）和吼猴（howler monkey）都属于灵长目；狮子（lion）和马（horse）都属于哺乳纲；蝎子（scorpion）和狼蛛（tarantula）都属于蛛形纲。这三组生物的亲缘关系都比短吻鳄和蚯蚓近。

Answer:

D. alligator and earthworm