According to Wieland Willker in his Online Textual Commentary on the Greek Gospels, Mark (including the long ending) has 362 Textual Variation Units (TVUs, i.e. places where there are variants), Matthew has 410, and Luke has 427. This appears to suggest that there is less variation in the mss of Mark than in Matthew or Luke, but this is only because Mark is roughly 40% shorter than Matthew and Luke. Instead, when looking at the frequency of the variants the picture is quite different.
Matthew and Luke are similar, with an average of 44.7 and 45.6 words per variant respectively, while in Mark the variants are much more frequent, with only 31.2 words per variant, i.e. variants are approximately 45% more frequent in Mark than in Matthew or Luke. In addition, whereas in both Matthew and Luke there are typically only a few different readings at each variant (often just the ‘critical’ and ‘majority’ text readings), in Mark there are often many different readings.
In the list below each row identifies the Markan verses in which Willker records a variant with 5, 6, 7, 8, etc. different variant readings. For example, Mk 3:31 has a variant with 5 different readings, while Mk 8:7 has a variant with 14 different readings. For reference, verses with no parallels in Luke's Great Omission are marked in red.
5. Mk 3:31, 4:11, 6:9, 6:23, 9:45, 10:11-12, 12:27, 14:51, 14:65, 15:44,
6. Mk 1:40, 5:13, 6:3, 7:8, 7:35, 8:15, 8:26, 9:47, 10:30, 11:6, 12:30, 12:41, 14:25, 14:36, 14:41, 14:62, 15:20
7. Mk 8:13, 8:25, 9:3, 9:23, 10:36, 11:8, 12:25, 12:31, 14:5, 14:19, 14:69, 15:36
8. Mk 2:19, 4:40, 5:12, 7:2, 7:33, 9:41, 11:3, 12:33, 13:8b, 14:70, 14:72
9. Mk 1:27, 4:28, 6:44, 6:45, 6:51, 12:21-22
10. Mk 3:3, 4:36, 12:17, 13:8a, 14:31
11. Mk 8:10
12. Mk 12:29
13. Mk 6:16, 6:33
14 Mk 8:7
It can be seen from this that there are many verses in Mark with multiple different variant readings, with several having 10 or more different readings. While both Matthew and Luke do have variants with multiple readings, variants are both more frequent and have more different readings in Mark than in either Matthew or Luke. Why this is so is not known, but it does suggest that at least some of the early copies of Mark may not have been written by professional scribes, or that the early text was more ‘fluid’ because it was not viewed as important to copy every word accurately. There is also the possibility that there were only a few early copies, and that those suffered damage, either from overuse, or simply due to being kept in hot and/or humid conditions, and led to variants in later copies.
The pages below discuss textual issues particular to the gospel of Mark, several of which focus on variants and other textual peculiarities that suggest that Mark underwent a greater degree of change than did Matthew or Luke:
Fatigue in Mark – or Damage to Mark? Do various odd errors in Mark indicate 'fatigue' by aMark when using Matthew as a source, or something completely different?
Mark 1:1-3 - The Short Beginning: Was the beginning of Mark defective at some point? What we see in Mark today suggests that it was.
Mark 1:41 - Angry or Compassionate?: When Jesus healed the leper, was he angry, or moved with compassion?
Mark 2:27-28 - The Sabbath: Was The Sabbath Made for Man, or for The Son of Man?
Mk 3:19b-22 - Mad Jesus and Beelzebub: Did Jesus' family think he was mad, or is this a textual problem?
Mark 11:11 The Non-Triumphal Entry The multitude who travel to Jerusalem with Jesus disappear when he enters the city. Where did they go?
Mark 16:9-20 - The Long Ending: The long ending of Mark (vv. 16:9-20) is generally believed to be a later addition. If so, where did it come from?