Studies on Experimental Haploidy in Salamander Larvae

Kaylor, C. T.

doi:10.2307/1537914

Cited by 6 publications

(3 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This parallel array correlates with the direction of cortical rotation. Cytoplasmic asters also have been described in the oogenesis of the salamander Triturus viridescens [61] and several anurans (see Additional file 1), related to cortical and germ plasm movements [11,12,27,62-65]. …”

Section: Developmental Similarities In Protostomes and Deuterostomesmentioning

confidence: 99%

“…Cytasters also take over the function of early cell divisions when parthenogenesis is artificially induced in the pig and rabbit [42,43]. In the salamander Triturus , in experiments on androgenic development, eggs are fertilized in the absence of the sperm-derived centrosome, so cytasters must organize the early cell divisions [61]. In all the cases mentioned above, cortical reorganization and cell divisions proceed normally, in the absence of a sperm-derived centrosome.…”

Section: Developmental Similarities In Protostomes and Deuterostomesmentioning

confidence: 99%

See 1 more Smart Citation

Cortical cytasters: a highly conserved developmental trait of Bilateria with similarities to Ctenophora

Salinas‐Saavedra

Vargas

2011

EvoDevo

View full text Add to dashboard Cite

BackgroundCytasters (cytoplasmic asters) are centriole-based nucleation centers of microtubule polymerization that are observable in large numbers in the cortical cytoplasm of the egg and zygote of bilaterian organisms. In both protostome and deuterostome taxa, cytasters have been described to develop during oogenesis from vesicles of nuclear membrane that move to the cortical cytoplasm. They become associated with several cytoplasmic components, and participate in the reorganization of cortical cytoplasm after fertilization, patterning the antero-posterior and dorso-ventral body axes.Presentation of the hypothesisThe specific resemblances in the development of cytasters in both protostome and deuterostome taxa suggest that an independent evolutionary origin is unlikely. An assessment of published data confirms that cytasters are present in several protostome and deuterostome phyla, but are absent in the non-bilaterian phyla Cnidaria and Ctenophora. We hypothesize that cytasters evolved in the lineage leading to Bilateria and were already present in the most recent common ancestor shared by protostomes and deuterostomes. Thus, cytasters would be an ancient and highly conserved trait that is homologous across the different bilaterian phyla. The alternative possibility is homoplasy, that is cytasters have evolved independently in different lineages of Bilateria.Testing the hypothesisSo far, available published information shows that appropriate observations have been made in eight different bilaterian phyla. All of them present cytasters. This is consistent with the hypothesis of homology and conservation. However, there are several important groups for which there are no currently available data. The hypothesis of homology predicts that cytasters should be present in these groups. Increasing the taxonomic sample using modern techniques uniformly will test for evolutionary patterns supporting homology, homoplasy, or secondary loss of cytasters.Implications of the hypothesisIf cytasters are homologous and highly conserved across bilateria, their potential developmental and evolutionary relevance has been underestimated. The deep evolutionary origin of cytasters also becomes a legitimate topic of research. In Ctenophora, polyspermic fertilization occurs, with numerous sperm entering the egg. The centrosomes of sperm pronuclei associate with cytoplasmic components of the egg and reorganize the cortical cytoplasm, defining the oral-aboral axis. These resemblances lead us to suggest the possibility of a polyspermic ancestor in the lineage leading to Bilateria.

show abstract

Section: Developmental Similarities In Protostomes and Deuterostomesmentioning

confidence: 99%

Section: Developmental Similarities In Protostomes and Deuterostomesmentioning

confidence: 99%

Cortical cytasters: a highly conserved developmental trait of Bilateria with similarities to Ctenophora

Salinas‐Saavedra

Vargas

2011

EvoDevo

View full text Add to dashboard Cite

show abstract

“…The high mortality of androgenetic salamander eggs is correlated with abnormal mitosis (197). Maternal inheritance was found in species hybrids of sea urchins (198) and in the inheritance of the number of lumbar vertebrae in the mouse (199).…”

Section: Developmental Geneticsmentioning

confidence: 99%