? asked in 科學生物學 · 1 decade ago

Biology Questions. NEED HELP!!

(1)

One child in 3500 is born with a particular metabolic defect which results from a homozygous recessive genotype. Assuming Hardy-Weinberg Equilibrium:

a. What is the estimated frequency of this recessive allele?

b. What is the estimated frequency of heterozygous "carriers" of this defect?

(2)

In the diploid ancestor of our modern bread wheat (Triticum aestivum), resistance to a particular fungal pathogen is controlled by a dominant allele at a single locus. Assume that a population of this diploid wheat is in Hardy-Weinberg equilibrium and that the frequency of the dominant (resistance) allele is 0.57

a. What percentage of the population is phenotypically resistant to the pathogen?

b. Assume that all susceptible individuals in this population are eventually killed by fungal infections before they reproduce. What is the frequency of the recessive (susceptibility) allele among the survivors? (HINT: count the alleles)

c. Assume that the surviving plants cross-pollinate randomly and that each plant produces the same number of seeds. What percentage of the seeds produced will eventually become plants that are susceptible to the fungus?

(3)

You sample 30000 Tsetse flies in a forest savanna habitat in central Africa. In this sample you determine that for a locus associated with Malathion resistance the flies have the genotype frequencies listed below.

M1M1: 8700 M1M2: 14400 M2M2:6900

After spraying the habitat with Malathion you obtain a sample of 5000 flies with the genotype frequencies listed below.

M1M1: 1350 M1M2: 1450 M2M2:2200

a. What are the relative fitnesses (W) of each genotype after the spraying?

M1M1:

M1M2:

b. Is this an example of heterozygote advantage? Why or why not.

Update:

抱歉,我也很想用中文

可是我不知道這些東西要怎麼翻譯成中文=(

因為我也不知道他們的中文是什麼

不過好吧

我拿第三題試試看!

在中非州的森林裡的薩凡納生態區裡面有30000個舌蠅(采采蠅?)樣本。

從這些樣本裡面,有農藥抗體的蒼蠅的觀測性狀是:

M1M1:8700

M1M2:14400

M2M2:6900

在使用了農藥之後你有5000個蒼蠅樣本。

下面是他們表現型性狀的頻率:

M1M1:1350

M1M2:1450

M2M2:2200

A)請問在使用了農藥之後,下列基因的相對適應(W)是多少?

M1M1

M1M2

B)這是一個雜合體優勢的例子嗎?

Update 2:

前面兩題真的很謝謝你耶!

我都看懂了=)

第三題我也不知道我的翻譯對不對

還請指教:D

Update 3:

哈哈你還真直接欸=3=

不過沒關係

我剛剛自己研究了一下

現在會算第三題了:)

謝謝你喔!

1 Answer

Rating
  • 光山
    Lv 5
    1 decade ago
    Favorite Answer

    你不能用中文嗎?

    Please use chinese.

    3500中有一個小孩是隱姓同型合子的。所以隱性基因頻率q的平方是1/3500。

    q=0.016903085094570

    p=0.983096914905430

    異型合子是p*q*2=0.033234741617712

    我是用excel算的

    q0.016903085094570 p0.983096914905430 pp0.966479544096574 qq0.000285714285714 pq20.033234741617712 sigma1.000000000000000

    抗性基因是顯性,頻率是0.57。

    p=0.57

    a.表現形是抗性者=pp+2pq=0.8151

    b.隱性合子死掉,剩下0.8151%的族群,其中含有q的是0.4902的部份,裡面有一半的基因座是q,所以新的q頻率是0.2451/0.8151=43/143

    c.新的q=43/143 容易死掉的是qq所以是0.090420069441048462027483006503986

    2010-10-19 01:24:42 補充:

    第三題我不會,請自行努力吧XD

Still have questions? Get your answers by asking now.