以下为某家族甲病(设基因为A、a)和乙病(设基因为B、b)的遗传家系图，其中Ⅱ-1不携带乙病的致病基因，下列叙述不正确的是（）。
- A.甲病的遗传方式为常染色体隐性遗传
- B.乙病的遗传方式为伴X染色体隐性遗传
- C.若Ⅲ-2与Ⅲ-4结婚，生一个两病皆患孩子的概率是1／24
- D.Ⅲ-5的基因型为aaXBXB或者aaXBXB
正确答案及解析
正确答案
解析
图中看出，Ⅱ-3和Ⅱ-4均不患甲病，生了一个患甲病的女儿，因此判断甲病为常染色体隐性遗传病，A项正确；Ⅱ-1和Ⅱ-2不患乙病，并且其中Ⅱ-1不携带乙病的致病基因，患病都为男性，致病基因只能来自Ⅱ-2，因此判断乙病为x染色体隐性遗传病，B项正确；Ⅲ-2的基因型为1／2AaXBXB或1／2 AaXBXb，Ⅲ-4的基因型为1／3 AAXBY或2／3 AaXBY，他们生一个两病皆患孩子的概率=2／3 × 1／4 ×(1／2×1／4)=1／48，C项错误；由于Ⅱ-4的乙病基因不确定，因此Ⅲ-5的基因型aaXBXB或aaXBXb，D项正确。
包含此试题的试卷
你可能感兴趣的试题
我国保护少年儿童权益的专项法律是《中华人民共和国未成年人保护法》。（ ）
- 查看答案
根据以下材料，回答题
If you don′t think a phone is the rightgift for a lover, the smart choice this year is a smart phone.
For people who don′t read instructions
The easiest-to-use phone is the iPhone. It′sthat has pushed it to the No.1 selling position, surpassing the Motorola Razr.The iPhone′s touch screen is easy to operate and it′s also easy to customize (用户化). The iPhone can run allsorts of applications such as those help you to lose weight, identify a song onthe radio, find a restaurant or do many other things.
For the futurist
The T-Mobile G1 is very popular as it is thefirst phone to offer a Google browser, meaning that you′re getting the real webon your phone, but it′s the phone′s potential that qualifies it for the futurist.The exciting applications are interesting, but they don′t always work smoothly.Sometimes it is hard to use the applications it comes with. The system shouldimprove as it becomes more popular, so it holds great promise. With fewrestrictions on the design of applications for the phone,
the G1 could be the first phone toincorporate (整合) some of the coolest.
For the road warrior
The new BlackBerry Storm is something likethe equivalent (等同物) of a mullet--a business up front, party in the back. It stillincorporates the serious mail and organization features that have endeared (使受钟爱) these phones to business people. The 3.25-inch is bright anddetailed and it′s a decent size for watching videos on the go.
For the Luddite (反对技术进步的人)
For those who can′t handle buttons and newfeatures, there is the Samsung Jitterbug Dial. Some people are Luddites whojust want a few large buttons to make calls. That′s it, just calls. That makesit even easier to use an iPhone.
What would be the best title forthe passage (no more than 6 words)
________________________________________________________________________
- 查看答案
简述学生的义务。
- 查看答案
依据《普通高中英语课程标准》，语言有丰富的文化内涵。教师应根据学生的年龄特点和__________ ，逐步扩展文化知识的内容和范围。
- 查看答案
计算机软件是指（ ）。
-
- A.计算机程序
- B.源程序和目标程序
- C.源程序
- D.计算机程序及有关资料
- 查看答案