Nonrandom expression of lactate dehydrogenase isozymes in the lizard family xantusiidae

Abstract A preliminary study of allozyme evolution in the lizard family Xantusiidae revealed the complete absence of expression of the A 1 B 3 lactate dehydrogenase heterotetramer isozyme in both muscle and liver tissue in 17 taxa surveyed. The four-banded LDH pattern resulting from this loss is postulated te be a derived (synapomorphic) character state for the entire family, perhaps shared with the Scincidae. Additional derived character states were observed to have evolved in parallel in several lineages within the Xantusiidae. Loss of the A 3 B 1 asymmetrical heterotetramer appears to have occurred a minimum of four times, and one species, Lepidophyma tuxtlae , also appears to have lost the B 4 homotetramer, having only a two-banded LDH isozyme pattern (A 4 and A 2 B 2 ).