# The MEME Suite

## Motif-based sequence analysis tools

## gendb

### Usage:

`gendb [options] <sequence count>`

### Description

gendb generates the specified number of random sequences using a Markov model. The sequence lengths are selected uniformly at random within the range specified by --minseq and --maxseq.

### Input

#### <sequence count>

The number of random sequences to generate.

### Output

Writes the sequences in FASTA format to standard output.

### Options

Option | Parameter | Description | Default Behavior
--- | --- | --- | ---
General Options
--alph | file | Generate random sequences using the alphabet defined in file file, an alphabet definition file. Note that this overrides the --type option. | Protein sequences are generated unless overridden using the --type option.
--ambig | ambig fraction | Sets the fraction of symbols that will be ambiguous (overrides --type) | The default depends on the --type option.
--bfile | file | Sets the background model used to generate the sequences from a file in background model format. | For the standard DNA and Protein alphabets a built-in 0-order background is used. If a non-standard alphabet is provided without a background then a uniform frequency distribution is used.
--order | n | Load the background model up to order n. | Load the background model completely.

--type

0|1|2|3|4

Allowed types are:

- 0 = Protein with 1% ambiguous symbols (default)
- 1 = DNA with 1% ambiguous symbols
- 2 = codons (ignores -bfile)
- 3 = DNA without ambiguous symbols
- 4 = Protein without ambiguous symbols

If an alphabet is not specified with the --alph option then protein sequences are generated.

--minseq | min | Minimum sequence length. | The minimum sequence length is 50.
--maxseq | max | Maximum sequence length. | The maximum sequence length is 2,000.
--dummy |  | Print a "dummy" sequence record before the generated sequences. The "dummy" sequence record is a a FASTA header line listing the gendb parameters but not followed by any sequence lines. |
--seed | seed | Seed for random number generator. |