Team:BNU-China/Model5
Number of hgRNA Required
Introduction
We constructed a universal method for predicting the desired number of variants in the case of knowing number of cells to be uniquely marked at a known level of significance. It allows users to predict the number of hgRNAs they will use based on their actual needs when performing lineage tracing.
Models and Results
The parameters introduced are as follows:
We define the singleton probability as the probability that a mutant uniquely marks a cell:
Since we could not accurately estimate the probability of each mutant, we made simplification. Assuming that,
Substitute it into the equation above, therefore:
In this experiment, we took mice as an example. An
adult mouse has about 12 billion cells, so we take 
. Since N is the value to be
estimated, we set 
as the range of N in Matlab and drew the variation diagram of
with the change of N:
Figure 1. the ideal singleton probability of each cell under different numbers of mutant
As described in the part of estimating the total
number, the number of variants which can be produced by a single hgRNA is 1401 in total. To
simplify it, here the ideal condition is considered. That is, assuming that each hgRNA works
independently, then the total number of variants produced by X hgRNAs is 
Discussion
The above results show that four hgRNAs could be used to label all cells in a mouse at the 95% significance level in theory in our experiment. However, considering the fact that the interaction relationship between hgRNA is unknown, there is a possibility that hgRNAs introduced in the experiment interplay with each other. So we speculated that the actual number of hgRNAs required should be than the theoretical number.
Any users who want to use our system can change the C value according to the number of cells to be uniquely labeled and use the same method to the ideal conclusion.
Postcode:100875
Email：igem2020bnu_china@163.com
© 2020. All Right Reserved. Designed by BNU-China