J Syst Evol ›› 1984, Vol. 22 ›› Issue (5): 360-366.

• Research Articles • Previous Articles     Next Articles

Biochemical Systematics of Gymnosperms (2), Seed Protein Peptides of Pinaceae

Hu Zhi‐Ang, Liu Zhang‐Jiang, Wang Hong‐Xin   

  1. (Institute of Botany, Academia Sinica, Beijing)
  • Published:1984-10-18

Abstract: By means of SDS linear gradient polyacrylamide gel electrophoresis, seed protein peptides of 50 species belonging to 10 genera of Pinaceae were analysed. A major peptide possessing molecular weight about 45000 daltons is shared by every species in Pinaceae. There are many peptides of higher molecular weight in seeds, but their content is very low. In order to make a series of quantitative comparisons between any two taxa, we define “peptide distance” as follows: number of different peptides between 2 taxa peptide distance= ----------- total number of peptides in 2 taxa In the following table, the peptide distances of some genera are shown together with other molecular data about Pinaceae.

genus ancientry of genus antigen distance zymogram distance peptide distance
Larix Miocene to now (25My) 0 0 0.08
Cedrux Pseudotsuga Keteleeria Oligocene to now (35My) _ _ _ 0 0.17 0.29 _ _ _
Tsuga Abies Eocene to now (57My) 1.0 _ _ 0.44 _ 0.35
Picea Late Cretaceous-(67-100 My) 0.5 0.30 0.18
Pinus Early Cretaceous-(100-130My) 2.3 0.67 0.39
From the data cited above, there are positive correlation between molecular data and the ancientry of genera in Pinaceae. Therefore, the rate of molecular evolution seems stable. Based on the data of peptide distances, it is suggested that the variation be discontinuous between the genera, but continuous within a genus. A comparison between molecular and morphological evolution indicates that the two evolutions are different not only in rate but in mechanism as well.

Key words: align=left Pinaceae, seed protein peptides, molecular evolution