convert dataframe without header to dictionary with a row of number
Works for me with numbers as headers:

import pandas as pd
df = pd.DataFrame({'1': [1, 2],
                 '2': [0.5, 0.75]},
                 index=['row1', 'row2'])
df.to_dict()


Output:

{'1': {'row1': 1, 'row2': 2}, '2': {'row1': 0.5, 'row2': 0.75}}


You may also specify column names when you read the data:

Cov = pd.read_csv("path/to/file.txt", 
                  sep='\t', 
                  names=["Sequence", "Start", "End", "Coverage"])


See: https://stackoverflow.com/questions/34091877/how-to-add-header-row-to-a-pandas-dataframe