The endochondral ossification of hindlimb is essential to a bird’s ability to stand,walk and fly.Most hindlimb is ossified in the embryos before hatching in precocial birds.However,the molecular mechanisms of hindlim...The endochondral ossification of hindlimb is essential to a bird’s ability to stand,walk and fly.Most hindlimb is ossified in the embryos before hatching in precocial birds.However,the molecular mechanisms of hindlimb ossification in birds is still unclear.Therefore,we tried to examine the process of hindlimb ossification and its molecular regulation by using an animal model—Japanese Quail(Coturnix japonica).We selected four critical stages(Embryo Day:E6,E8,E12 and E16) of skeletal development of embryonic quails for hindlimb skeleton staining to show the process of endochondral ossification and to examine the molecular regulation of endochondral osteogenesis by RNA-Seq analysis.The results showed that ossification became increased with embryonic development and most hindlimb was ossified before hatching.RNA-Seq analysis revealed that various signaling pathways were involved with endochondral ossification with thyroid hormone signaling and WNT signaling pathway particularly enriched.Moreover,the expression levels of 42 genes were continuously upregulated and 14 genes were continuously downregulated from E6 to E16.The present study might provide new insights into complex molecular mechanisms in regulation of endochondral ossification.展开更多
Passerines moult during various life-cycle stages.Some of these moults involve the retention of a variable quantity of wing and tail feathers.This prompts the question whether these partial moults are just arrested co...Passerines moult during various life-cycle stages.Some of these moults involve the retention of a variable quantity of wing and tail feathers.This prompts the question whether these partial moults are just arrested complete moults or follow different processes.To address it,I investigated whether three relevant features remain constant across partial and complete moults:1) moult sequence(order of activation) within feather tracts(e.g.,consecutive outward moult of primaries) and among tracts(e.g.,starting with marginal coverts,followed by greater coverts second,tertials,etc.);2) dynamics of moult intensity(amount of feathers growing along the moult progress);and 3) protection of wing quills by overlapping fully grown feathers.To study the effect of moult completeness on these three features,I classified moults of 435 individuals from 61 species in 3 groups:i) complete and partial,ii) without and iii) with retention of feathers within tracts.To study the effect of life-cycle stage,I used postbreeding,postjuvenile,and prebreeding moults.I calculated phylogenetically corrected means to establish feather-moult sequence within tracts.I applied linear regression to analyse moult sequence among tracts,and polynomial regression to study the dynamics of moult intensity as moult progresses.Sequence and intensity dynamics of partial moults tended resemble those of the complete moult as moult completeness increased.Sequence within and among feather tracts tended to shift as moult intensity within tracts and number of tracts increased.Activation of primaries advanced in relation to the other feather tracts as number of moulted primaries increased.Tertial quills were protected by the innermost greater covert regardless of moult completeness.These findings suggest that moult is a self-organised process that adjusts to the degree of completeness of plumage renewal.However,protection of quills and differences among species and between postjuvenile-and prebreeding-moult sequences also suggest an active control linked to feather function,including protection and signalling.展开更多
The Asian leaf litter toad genus Leptobrachella contains more than 100 species widely distributed in southwestern Asia.However,the systematic profiles of this group remain unresolved.Osteological morphology is importa...The Asian leaf litter toad genus Leptobrachella contains more than 100 species widely distributed in southwestern Asia.However,the systematic profiles of this group remain unresolved.Osteological morphology is important for taxonomic and phylogenetic studies.However,few studies have focused on the osteology of the genus.Herein,we comprehensively described the osteological features of a representative species L.bijie based on micro-CT scanning and double-staining methods.The results show that the skull of adult L.bijie is well-ossified,exhibiting sexual dimorphism and minimal intraspecific variation.The skull length is slightly greater than the width,with the maxilla slightly overlapping with the quadratojugal.The nasal connects with the sphenethmoid in males,but only part or not connects with the sphenethmoid in females.The transverse processes of the sacrum are robust and symmetrically butterfly-shaped,and the presacral vertebrae are procoelous.The pectoral girdle is arciferous.The phalangeal formula is 2-2-3-3 for the hand,and 2-2-3-4-3 for the foot.This study provides the first detailed and comprehensive osteological accounts of the genus Leptobrachella.展开更多
基金supported by the National Natural Science Foundationof China (No. 33372201)。
文摘The endochondral ossification of hindlimb is essential to a bird’s ability to stand,walk and fly.Most hindlimb is ossified in the embryos before hatching in precocial birds.However,the molecular mechanisms of hindlimb ossification in birds is still unclear.Therefore,we tried to examine the process of hindlimb ossification and its molecular regulation by using an animal model—Japanese Quail(Coturnix japonica).We selected four critical stages(Embryo Day:E6,E8,E12 and E16) of skeletal development of embryonic quails for hindlimb skeleton staining to show the process of endochondral ossification and to examine the molecular regulation of endochondral osteogenesis by RNA-Seq analysis.The results showed that ossification became increased with embryonic development and most hindlimb was ossified before hatching.RNA-Seq analysis revealed that various signaling pathways were involved with endochondral ossification with thyroid hormone signaling and WNT signaling pathway particularly enriched.Moreover,the expression levels of 42 genes were continuously upregulated and 14 genes were continuously downregulated from E6 to E16.The present study might provide new insights into complex molecular mechanisms in regulation of endochondral ossification.
文摘Passerines moult during various life-cycle stages.Some of these moults involve the retention of a variable quantity of wing and tail feathers.This prompts the question whether these partial moults are just arrested complete moults or follow different processes.To address it,I investigated whether three relevant features remain constant across partial and complete moults:1) moult sequence(order of activation) within feather tracts(e.g.,consecutive outward moult of primaries) and among tracts(e.g.,starting with marginal coverts,followed by greater coverts second,tertials,etc.);2) dynamics of moult intensity(amount of feathers growing along the moult progress);and 3) protection of wing quills by overlapping fully grown feathers.To study the effect of moult completeness on these three features,I classified moults of 435 individuals from 61 species in 3 groups:i) complete and partial,ii) without and iii) with retention of feathers within tracts.To study the effect of life-cycle stage,I used postbreeding,postjuvenile,and prebreeding moults.I calculated phylogenetically corrected means to establish feather-moult sequence within tracts.I applied linear regression to analyse moult sequence among tracts,and polynomial regression to study the dynamics of moult intensity as moult progresses.Sequence and intensity dynamics of partial moults tended resemble those of the complete moult as moult completeness increased.Sequence within and among feather tracts tended to shift as moult intensity within tracts and number of tracts increased.Activation of primaries advanced in relation to the other feather tracts as number of moulted primaries increased.Tertial quills were protected by the innermost greater covert regardless of moult completeness.These findings suggest that moult is a self-organised process that adjusts to the degree of completeness of plumage renewal.However,protection of quills and differences among species and between postjuvenile-and prebreeding-moult sequences also suggest an active control linked to feather function,including protection and signalling.
基金supported by West Light Foundation of The Chinese Academy of Sciences(Grant No.2021XBZG_XBQNXZ_A_006)National Natural Sciences Foundation of China(Grant Nos.:32270498 and 32070426)China Biodiversity Observation Networks(Sino BON-Amphibian and Reptile).
文摘The Asian leaf litter toad genus Leptobrachella contains more than 100 species widely distributed in southwestern Asia.However,the systematic profiles of this group remain unresolved.Osteological morphology is important for taxonomic and phylogenetic studies.However,few studies have focused on the osteology of the genus.Herein,we comprehensively described the osteological features of a representative species L.bijie based on micro-CT scanning and double-staining methods.The results show that the skull of adult L.bijie is well-ossified,exhibiting sexual dimorphism and minimal intraspecific variation.The skull length is slightly greater than the width,with the maxilla slightly overlapping with the quadratojugal.The nasal connects with the sphenethmoid in males,but only part or not connects with the sphenethmoid in females.The transverse processes of the sacrum are robust and symmetrically butterfly-shaped,and the presacral vertebrae are procoelous.The pectoral girdle is arciferous.The phalangeal formula is 2-2-3-3 for the hand,and 2-2-3-4-3 for the foot.This study provides the first detailed and comprehensive osteological accounts of the genus Leptobrachella.
