reading a 1000 Hz (sample freq) signal using 200 Hz sample frequency
How is reading the 1000 Hz signal using 200 Hz sampling frequency going to affect my data?


Unless the bandwidth of the data is really really low compared to the sampling frequency, it is most likely going to destroy the integrity of the data. 

As Makato said in the comments, you need to sample at at least twice the frequency of the highest frequency in the signal. So if your 1000 Hz signal has data at 1000 Hz, you need to sample it at at least 2000 Hz. 

However, if your audio signal's sampling rate is unneccesarily high - in your case by a factor of 10 compared to the highest data-carrying frequency in the signal - you might be in luck.

See Nyquist–Shannon sampling theorem for a less simplified explanation.