| 查看: 758 | 回复: 4 | |||
| 当前只显示满足指定条件的回帖，点击这里查看本话题的所有回帖 | |||
yucheng9255木虫 (著名写手)
|
[求助]
国外第一次上遗传课就被课后作业难倒，大家帮我看看，急！！
|
||
|
Graduate student Evert Explorer found an old ear of corn in Mexico that contained both plump kernels and shrunken kernels. Shrunken seed accounted for 25% of the total seed (a 3 to 1 segregation ratio). Curious about the genetic cause of the shrunken seed, he brought the seed back to the UF, and planted these seeds as well as mutant seeds of three homozygous recessive mutants, termed shrunken-2, brittle-1 and brittle-2. These mutants are phenotypically indistinguishable from the mutant seed found in Mexico. Phenotypically mutant seed from Mexico did not germinate whereas non-mutant, or plump, seed from the ear did. Six plants derived from the plump seed were crossed onto each of the three mutants. Whereas all crosses onto plants from shrunken-2 and brittle-1 mutants yielded all plump seed, crosses of four of the six plants onto plants from the brittle-2 seeds gave rise to ears that were 50% plump and 50% shrunken. What is the cause of the mutant seed found in Mexico? Why didn’t all crosses onto brittle-2 yield mutant seed? What is the origin of the 50:50 ratios in the brittle-2 crosses that segregated mutant seed? |
回复此楼» 猜你喜欢
不合理蛙科研实验中的趣事：实验器材的 “乌龙”
已经有0人回复
-
不合理蛙科研实验中的趣事：和实验材料的 “斗智斗勇”
已经有0人回复
-
化学工程及工业化学论文润色/翻译怎么收费?
已经有139人回复
-
蛋白质检测：精准分析，解锁生物分子的密码
已经有0人回复
-
不合理蛙科研实验之小鼠实验：严谨设计，解析生命机制的重要载体
已经有0人回复
-
不合理蛙科研实验之重金属检测：精准筛查，守护健康与环境的防线
已经有0人回复
-
不合理蛙科研实验之“蛙测重金属我背锅三千”
已经有0人回复
-
不合理蛙科研实验之“鼠逃三次我发三篇SCI”
已经有0人回复
-
纳米粒度分析
已经有3人回复
-
林科院林化所招收材料与化工专业硕士，坐标南京
已经有0人回复
» 本主题相关价值贴推荐，对您同样有帮助:
- 大家帮我看看啊，我做的酶切反应到底是怎么回事呢？急急急！
已经有15人回复
- 第一次发表文章，大家帮我看看编辑回复，是什么问题？
已经有9人回复
- 急：大家帮我看下：金相照片上怎么这么多浮凸的点啊
已经有28人回复
- 请大家帮我看看怎么回复这样的proof,在线等。急！
已经有5人回复
- 第一次写文章，大家帮我看看这种情况能不能发表
已经有10人回复
- 刚刚和老外视频，简直就是运气啊，大家来帮我看看我的offer模板有什么问题么？
已经有10人回复
- 【问题求助】说说我的心里状态，大家帮我看看是不是该去看心理医生了？
已经有28人回复
- 第一次投稿被拒了，大家帮我看看还有没有希望修改后重投。谢谢！！！！！
已经有10人回复
- 无金币。。哭求帮助。。“被拒，大家帮我看看，是重投还是改投？”
已经有16人回复
- 第一次投稿,评审结果出来了,大家帮我看看好吗
已经有36人回复
- 【求助】大家帮我看下这段话具体是什么意思，我每句能看懂，但整体不会理解
已经有14人回复
irenescbg
金虫 (小有名气)
- MolEPI: 1
- 应助: 7 (幼儿园)
- 金币: 1673.8
- 散金: 93
- 红花: 1
- 帖子: 89
- 在线: 24.2小时
- 虫号: 1947397
- 注册: 2012-08-20
- 专业: 植物生理与生化
【答案】应助回帖
★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★ ★
1949stone: 金币+3, A+ 2012-08-27 16:54:00
yucheng9255: 金币+10 2012-08-28 07:28:58
1949stone: 金币+3, A+ 2012-08-27 16:54:00
yucheng9255: 金币+10 2012-08-28 07:28:58
|
That's very easy..... 1. brittle-2 mutation in the seeds found in mexico caused the shrunken phenotype. 2. brittle-2 is a RECESSIVE mutant. When plump seeds carried WT genes, the F1 progeny of the cross has heterozygous genotype. These seeds are not shrunky. 3. If the plump seeds are heterozygous (bB), when these plants were crossed to brittle-2 (bb), half of the progeny will be bB, and half will be bb. bB genotype will result in a plump seed while bb results in shrunky seeds. |
4楼2012-08-27 16:18:23
irenescbg
金虫 (小有名气)
- MolEPI: 1
- 应助: 7 (幼儿园)
- 金币: 1673.8
- 散金: 93
- 红花: 1
- 帖子: 89
- 在线: 24.2小时
- 虫号: 1947397
- 注册: 2012-08-20
- 专业: 植物生理与生化
|
Sorry I made some mistakes and I didn't make some part clear. Here are the corrections. brittle-2 is allelic to the mutation that caused shrunken phenotype in the mexican line. The other two were not allelic. shrunken mutation is recessive. Same with brittle-2. Among the 6 plump plants used for cross, two have willd type allele of brittle gene while the rest four are heterozygous. |
5楼2012-08-28 08:39:25
