| Cursorial locomotion involves many vital activities of organism,such as acquiring water and food resources,mating,and avoiding enemies.As predator and prey,cheetah?Acinonyx jubatus?and pronghorn?Antilocapra americana?co-evolved and became the two fastest land running mammals in the course of long-term chase and escape.Distantly related species adapt to similar environments or survival pressures,the similarity of morphology,physiology and even behavior is called convergent evolution.Although cheetah and pronghorn are distant relatives,compared with mammals of the identical body size,cheetahs and pronghorns are well-proportioned,slender limbs,and light bones.They both have enlarged nostrils,thickened airways,markedly enlarged heart and lungs,thickened blood vessels.They own extremely high content of muscle mitochondria,a large proportion of fast muscle fibers,increased hemoglobin and red blood cells;and the opening mouth and trajectory while running is semblable,too.However,studies on the convergence evolution at the molecular level have not been reported.Therefore,the genome-wide data of cheetah,pronghorn and their related species were used to carry out convergent evolution analysis at different levels of gene coding and non-coding,incluind convergence of amino acid,positive selection gene?PSG?,fast evolution gene?FEG?,accelerated evolution GO terms and accelerated evolution element?ACEE?.The main discoveries are as follows:Firstly,we identified one convergent amino acid site in ABCC8 gene.VEGFB and SCN5A gene were identified as convergent positive selection genes,as well as TBX18 and EP300 gene were selected as convergent fast evolution genes,which regulate heart and/or vessel;the positive selection genes and fast evolution genes are also significantly enriched in“Dilated cardiomyopathy?DCM?”,“Hypertrophic cardiomyopathy?HCM?”and“Adrenergic signaling in cardiomyocytes”,indicating that cheetah and pronghorn are likely to undergo convergent evolution in the cardiovascular system.Secondly,one convergent amino acid site was screened in CTNNA3 gene,and there are some accelerated evolution elements of cheetah and pronghorn mapped on it.MYH13 was identified as fast evolution gene,and ERBB4,PARD3B and PBX1 harboured accelerated evolution elements.Those genes regulate muscle contraction,bone and/or muscle development;the positive selection genes and fast evolution genes are significantly enriched in"Regulation of actin cytoskeleton",revealing that convergence evolution may occur in musculoskeletal system of cheetah and pronghorn.Finally,NRXN1 gene located a lot accelerated evolution elements,the alpha-type isoforms of which plays a role in the regulation of calcium channel activity and Ca?2+?-triggered neurotransmitter release at synapses and at neuromuscular junctions;fast evolution genes are significantly enriched in four KEGG pathways,including axon guidance,synapses,and neurotrophic factors,suggesting that the nervous systems of cheetahs and pronghorns may also undergo a certain convergent evolution.In addition,ionic functions and respiratory system related genes and KEGG pathways are also significantly enriched.This study is to explore the molecular mechanisms that may exist in adaption of cursorial locomotion by convergent evolution analysis across the genome-wide level of cheetah and pronghorn,and laying a systematic theoretical basis and tight foundation for further research on the cardiovascular disease and skeletal muscle development in ruminants. |
PDF Full Text Request