Should a genesis block have a previous block?

[aljones15]

From the documents:

EXAMPLE 1: Example genesis block
{
  "@context": "https://w3id.org/web-ledger/v1",
  "id": BLOCK_ID,
  "type": "LedgerConfigurationBlock",
  "ledgerConfig": {
    "id": LEDGER_ID,
    "type": "LedgerConfiguration",
    "name": "example",
    "description": "This is an example ledger.",
    "storageMechanism": STORAGE_DATA_STRUCTURE,
    "consensusAlgorithm": CONSENSUS_ALGORITHM,
  "previousBlock": {
    "hash": "urn:sha256:0000000000000000000000000000000000000000000000000000000000000000"
  },
  "signature": SIGNATURE_VALUE
}

if a genesis block is the first block why does it have a previousBlock?

[mattcollier]

@aljones15 can you look in at one of your ledger block collections and see if we're actually doing that now?