Molecular origins of rapid and continuous morphological evolution

Fondon, John W.; Garner, Harold R.

doi:10.1073/pnas.0408118101

Cited by 530 publications

(578 citation statements)

References 32 publications

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“…Evidence of tandem gene duplication and high levels of polymorphism suggests that spidroins are naturally selected to maintain diversity. The presence of long arrays of tandem repeats in spidroins, reminiscent of those that facilitate rapid variation on microbial cell surfaces 61 and morphological plasticity in mammals 62 , also suggests a gene family undergoing continuous evolution. In particular, N. clavipes spidroin gene phylogenies ( Fig.…”

Section: Discussionmentioning

confidence: 99%

The Nephila clavipes genome highlights the diversity of spider silk genes and their complex expression

et al. 2017

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More than 380 million years of evolution have produced >46,000 extant spider species, exhibiting an incredible diversity of silks used for prey capture and reproduction [1][2][3] . Spider silks can be stronger than steel and tougher than Kevlar, yet are much lighter weight than these manmade materials 4 . Silks vary in extensibility 5 , are temperature resilient 6 , can enable electrical conduction 7 , and can inhibit bacterial growth while being nearly invisible to the human immune system 8 . Thus, novel materials derived from spider silks offer tremendous potential for medical and industrial innovation. To take advantage of their desirable properties, we must learn more about spider silk genetic structure, functional diversity, and production.A female orb-weaving spider can have up to seven morphologically differentiated types of silk glands, each believed to extrude a distinct class of silk with biophysical characteristics resulting from the expression of a unique combination of silk genes in that gland 9,10 . The silk classes of a typical 'gluey silk' orb-weaver (Araneoidea) female include (i) major ampullate silk, which exhibits great tensile strength and is employed in draglines, bridgelines, and web radii 11,12 ; (ii) minor ampullate silk, used for inelastic temporary spirals during web building 11,12 ; (iii) cement-like piriform silk that bonds fibers together and to other substrates 13,14 ; (iv) strong, yet flexible aciniform silk used for prey wrapping and egg case insulation 15 ; (v) tubuliform and cylindriform silk that constitutes the tough outer layer of egg cases 16,17 ; (vi) flagelliform silk that exhibits unparalleled extensibility and is used in the capture spiral 18,19 ; and (vii) the viscous and sticky aggregate silk that aids in prey capture [20][21][22][23][24] . Many spider species produce just a subset of these silk classes, and some produce yet other silk types, including cribellate silk 25 . Each species possesses an assortment of specialized gland types that are thought to produce distinct classes of silks to fit specific needs 9,26,27 .Spider silks are composed primarily of spidroin proteins (where a 'spidroin' is a spider fibroin [28][29][30][31] ) that, by convention, have been named and classified according to the specific silk gland in which they were first discovered. Spidroin proteins have conserved N-and C-terminal domains that flank long runs of repeated motifs 32-34 , the composition and number of which confer specific physical properties to silks 27 . Yet, despite decades of research on orb-weaver silks, there is incomplete knowledge of all the spidroins within an orb-weaver species.Adding to the sampling of sequences obtained from targeted investigations, the assembly of the velvet spider (Stegodyphus mimosarum) genome yielded 19 spidroins, the largest collection from any single species 27 . Owing to the challenges of assembling arrays of repeats, several of the S. mimosarum spidroin sequences are incomplete, without the sequences encoding N-and C-terminal domains anchored ...

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Section: Discussionmentioning

confidence: 99%

The Nephila clavipes genome highlights the diversity of spider silk genes and their complex expression

et al. 2017

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“…These repeat sequences are longer in the chicken, mouse, and human orthologs of the gene. The high ratio of glutamine to alanine in Xenopus may indicate a relatively higher level of Runx2 transcriptional activity (Fondon and Garner, 2004). Xenopus, zebrafish, and chicken sequences lack a 22-amino acid stretch found in the mouse sequence beginning with the amino acid sequence DDTAT (underlined in Fig.…”

Section: Xenopus Laevis Runx2 Gene Structurementioning

confidence: 99%

Runx2 is essential for larval hyobranchial cartilage formation in Xenopus laevis

Kerney

Gross

Howard

2007

Developmental Dynamics

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The vertebrate transcription factor protein Runx2 is regarded as a "master regulator" of bone formation due to the dramatic loss of the osseous skeleton in the mouse homozygous knockout. However, Runx2 mRNA also is expressed in the pre-hypertrophic cartilaginous skeleton of the mouse and chicken, where its developmental function is largely unknown. Several tiers of Runx2 regulation exist in the mouse, any of which may account for its seeming biological inactivity during early stages of skeletogenesis. Unlike mouse and chicken, zebrafish require Runx2 function in early cartilage differentiation. The present study reveals that the earlier functional role of Runx2 in cartilage differentiation is shared between zebrafish and Xenopus. A combination of morpholino oligonucleotide injections and neural crest transplants indicate that Runx2 is involved in differentiation of the cartilaginous hyobranchial skeleton in the frog, Xenopus laevis. Additionally, in situ hybridizations show runx2 mRNA expression in mesenchymal precursors of the cartilaginous skull, which reveals the earliest pre-patterning of these cartilages described to date. The early distribution of runx2 resolves the homology of the larval suprarostral plate, which is one of the oldest controversies of anuran skull development. Together these data reveal a shift in Runx2 protein function during vertebrate evolution towards its exclusive roles in cartilage hypertrophy and bone differentiation within the amniote lineage. Developmental Dynamics 236:1650 -1662, 2007.

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“…These have led to the mapping of disease loci for a variety of diseases including metabolic disorders 22,23 , blindness [24][25][26][27][28] , cancer 29,30 neurologic disorders 31,32 , hip dysplasia 33 epilepsy 34 , as well as several morphologic traits 35,36 . In addition, the advancement of a framework for how to study complex canine traits 37 has led to deepening of our knowledge about the organization of the canine genome 38,39 and how it relates to morphological variation between breeds.…”

Section: Introductionmentioning

confidence: 99%

Finding cardiovascular disease genes in the dog

Parker

Meurs

Ostrander

2006

Journal of Veterinary Cardiology

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Recent advances in canine genomics are changing the landscape of veterinary biology, and by default, veterinary medicine. No longer are clinicians locked into traditional methods of diagnoses and therapy. Rather major advances in canine genetics and genomics from the past five years are now changing the way the veterinarian of the 21 st century practices medicine.First, the availability of a dense genome map gives canine genetics a much needed foothold in comparative medicine, allowing advances made in human and mouse genetics to be applied to companion animals. Second, the recently released 7.5x whole genome sequence of the dog is facilitating the identification of hereditary disease genes. Finally, development of genetic tools for rapid screening of families and populations at risk for inherited disease means that the cost of identifying and testing for disease loci will significantly decrease in coming years.Out of these advances will come major changes in companion animal diagnostics and therapy. Clinicians will be able to offer their clients genetic testing and counseling for a myriad of disorders. Such advances are certain to generate healthier and more long lived dogs, improving quality of life for owner and pet alike. The clinician of the 21 st century, therefore, faces incredible opportunities as well as challenges in the management of genetic disease. In this review we summarize recent findings in canine genomics and discuss their application to the study of canine cardiac health.

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Molecular origins of rapid and continuous morphological evolution

Cited by 530 publications

References 32 publications

The Nephila clavipes genome highlights the diversity of spider silk genes and their complex expression

The Nephila clavipes genome highlights the diversity of spider silk genes and their complex expression

Runx2 is essential for larval hyobranchial cartilage formation in Xenopus laevis

Finding cardiovascular disease genes in the dog

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