Major Histocompatibility Complex Allele Persistence in Eurasia and America in the Genus Carduelis (Spinus) During Million Years

Abstract

Introduction:GenusCarduelis(Fringillidaefamily) includes goldfinches, siskins, redpolls, greenfinches and crossbills. Many of the species classified within this genus and other related genera have been grouped by using molecular systematics and the mitochondrial cytochrome b (mt cyt b) gene. According to this, the Eurasian siskin (C. spinus)is the only one extant direct ancestor of several North American finches; North American / South American radiations may have been originated by Eurasian siskin (or extinct relative). In the present work, we aim to perform a study of transpecies and transcontinental analyses of MHC (Major Histocompatibility Complex) Class I alleles in several genusCarduelis/Spinusspecies in order to draw evolutionary conclusions in several wild bird species belonging to the genusCarduelis / Spinus.Materials and Methods:Blood was taken from worldwide wild bird species. Passerine phylogeny was done after analysing mtDNA with Maximun Likelihood and Bayesian dendrograms. Major histocompatibility complex alleles were obtained by standard DNA cloning and sequencing.Results:We found two matches between MHC-I DNA alleles from different South American siskins at DNA level. Also, it was observed that the Eurasian siskin shares a protein with pine siskin and another with three South American siskins. Eight South American siskins species also share the same MHC protein. In addition, studied songbirds MHC class I intron 2 is longer than that ofGallus gallus.Conclusion:We have drawn the following conclusions: 1) We present the first direct evidence that “Minimal Essential MHC” does not exist for birds; one of its main definition characters,i.e.: small intron size does not hold for songbirds. 2) We also report that MHC genes transpecies evolution exist in birds by showing also for the first time that worldwide bird species keep the same MHC protein and DNA alleles. 3) New evidences on MHC alleles conservation from EurasianCarduelis spinus(most ancient) to South American siskins (most recent) during million years support that Eurasian siskin is the parental species for American GenusCarduelis (Spinus)species. It is uncertain whether Eurasian siskin (or extant relative) had initially an Holoartic distribution, including America.

Major histocompatibility complex complement (MHC) Bf alleles show trans species evolution between man and chimpanzee

“…A role for the alternative complement pathway in Systemic Lupus Erythematosus (SLE) has been shown 24 . Bb fragment is postulated to be important in SLE severity detection; the Bb fragment was not detected in the activated plasma samples from SLE patients, which suggest that activation of the alternative complement pathway may be a marker for severe SLE and that the Bb fragment may be playing a role in the development of this severe pathologic condition 21 .…”

“…This is the first described case of allelic trans species evolution in human/ primates MHC complement class III genes. MHC class II trans specific alleles between human and primates have been described 20 and also between MHC class I different bird species 21 .…”

Evolution and molecular interactions of major histocompatibility complex (MHC)-G, -E and -F genes

“…Much debate has occurred, because so many MHC different immune genes go close together in a short chromosome area across species from amniotes to humans during many million years [152][153][154]. This suggests that this set of genes may work together to save individual and species from external injuries, probably microbes, and associated self-recognition pathologies [3,64,155,156].…”

“…Keeping together a set of certain alleles set of all known immune-related genes may be more advantageous for survival (i.e. : MHC haplotypes rather than single genes) [159] and this may be the reason why all these genes are transmitted conjointly at least from amniotes to humans [3,64,154,158,160]. A search as towhy they are transmitted and work together is worth to follow at this point of MHC/ disease association nihilism.…”