update README

Author: QuKunLab

README.md

@@ -12,7 +12,7 @@ APEC can perform fine cell type clustering on single cell chromatin accessibilit
 
 #### 1.1 Requirements
 
-APEC requires Linux system (CentOS 7.3+ or Ubuntu 16.04+), as well as Python3 (3.6.8, not 3.7.x). If users want to build pseudotime trajectory with APEC, please install R (3.5.1) environment and monocle (2.10.0). Also, the following software are required for APEC:
+APEC requires Linux system (CentOS 7.3+ or Ubuntu 16.04+), as well as Python3 (3.6.8, not 3.7.x) and R (3.5.1+) environments. If users want to build pseudotime trajectory with APEC, please install monocle (2.10.0, http://cole-trapnell-lab.github.io/monocle-release/docs/) in R. Also, the following software are required for APEC:
 
     Bedtools: http://bedtools.readthedocs.io/en/latest/content/installation.html
     Meme 4.11.2: http://meme-suite.org/doc/download.html?man_type=web
@@ -37,7 +37,7 @@ Users can install APEC by:
 
     pip install APEC==1.1.0.11
 
-We suggest that users build a python 3.6.8 environment for APEC with **miniconda** or **anaconda**, since APEC is dependent on specific versions of python packages (see README.md in examples folder), and bedtools and meme suite (4.11.2) can be installed in conda enviroment too.
+We suggest that users build a python 3.6.8 environment for APEC with **miniconda** or **anaconda**, since APEC is dependent on specific versions of python packages (see README.md in examples folder). R packages (e.g. monocle 2.10.0), bedtools, and meme suite (4.11.2) can be installed in conda environment too.
 
 In Ipython, Jupyter-notebook or a python script, users can import packages of APEC by: