一道统计概率问题

是 否 +2 论坛币

k人 参与回答

经管之家送您一份

应届毕业生专属福利!

求职就业群

赵安豆老师微信：zhaoandou666

经管之家联合CDA

送您一个全额奖学金名额~ !

立即领取

感谢您参与论坛问题回答

经管之家送您两个论坛币！

+2 论坛币

Hidden Markov models have been successfully applied to a variety of

problems in molecular biology, ranging from alignment problems to gene finding and

annotation. let us consider a problem of finding CpG-islands in the human genome. Since

there is relative high chance that methyl-C will mutate to T except at the CpG-islands in the

promoter regions of genes, we’ll see more CpG-pairs in the CpG-islands than elsewhere.

Therefore, CpG-islands are useful markers for genes in human and some other organisms.

The question is that how to determine a segment of genome sequence from a CpG-island. For

instance, consider a DNA sequence of AGCGCGATC. Apply a HMM model that assumes a

transition probability matrix for the two states, CpG-island denoted by + and Non CpG-island

denoted by − as below:

                         right

Probability       +         −

            +       0.8       0.2

  Left

            −       0.9       0.1

The emission probability matrix is assumed to be:

Probability     A         C         G         T

      +         0.20     0.35     0.26     0.19

      −         0.35     0.15     0.10     0.40

These probabilities are made up here. In practice, they can be estimated through learning from

training data of the known genes. Calculate the probability of observing a DNA sequence of

AGCGCGATC under a probable state path − + + + + + − − − for the model assumed. What

is that probability under the path + + + + + − − − −?

扫码加我 拉你入群

请注明：姓名-公司-职位

以便审核进群资格，未注明则拒绝

分享0 收藏0 回帖

关键词：概率问题 统计概率 Successfully Probability Transition problems relative biology finding except