A possible common origin of ?Y-negative? human XX males and XX true hermaphrodites

1990 ◽  
Vol 84 (4) ◽  
Author(s):  
NacerEddine Abbas ◽  
JeanEdmond Toublanc ◽  
Chafika Boucekkine ◽  
Marianne Toublanc ◽  
NabeelA. Affara ◽  
...  
Keyword(s):  
Common Origin ◽  
Xx Males

scholarly journals III.—Morphological Studies on the Echinoidea Holectypoida and their Allies

1917 ◽  
Vol 4 (6) ◽  
pp. 249-256
Author(s):  
Herbert L. Hawkins
Keyword(s):  
Common Origin ◽  
Normal Type ◽  
The Third ◽  
Morphological Studies ◽  
Apical System ◽  
The Common

The characters of the apical system of a series of Holectypus hemisphæricus from the same horizon at two localities in Dorsetshire are analysed and described. It is found that the average relations of the plates of the system are different at the two localities, although certain numbers of identical forms occur at both. Out of 189 specimens (from both localities), 40 show serious departures from the normal type. These abnormalities are of three classes. One, the most prevalent, consists in the presence of madreporic pores on genital 3, in addition to the normal perforation of genital 2. This is regarded as a “progressive variant” in the direction of Discoides. The second, occurring in three specimens, consists in the interpolation of a supernumerary plate within the system. It is suggested that this may be either a “regressive variant” towards Acrosalenia, or a “progressive variant” towards Nucleolites (as illustrated by N.orlicularis). In neither case would this variation coincide with actual phyletic sequence, so that it is styled “parallel variation”. The third type of variant, seen in one specimen only, combines both the first and second types, and in addition shows an absence of genital 5 and a corresponding increase in the size of the posterior oculars, which meet round the back of the system. The variation in this specimen is interpreted as being “progressive” towards Discoides, “parallel progressive” or “regressive” towards Nucleolites or Acrosalenia respectively, and “progressive” towards Conulus. There are indications of a different series of variants in the Holectypus depressus from the Cornbrash. The high percentage of variation in the composition of the apical system of Holectypus is regarded as an indication of the evolutional activity of the genus, and of its near approximation in time and phylogeny to the common origin of many of the groups of Irregular Echinoids.

The morphogenesis of different giant viruses as additional evidence for a common origin of Nucleocytoviricota

2021 ◽  
Vol 49 ◽  
pp. 102-110
Author(s):  
Rodrigo AL Rodrigues ◽  
Fernanda G de Souza ◽  
Bruna L de Azevedo ◽  
Lorena CF da Silva ◽  
Jônatas S Abrahão
Keyword(s):  
Common Origin ◽  
Giant Viruses

Human XX males with Y single-copy DNA fragments

Nature ◽  
1984 ◽  
Vol 307 (5947) ◽  
pp. 172-173 ◽  
Author(s):  
Georges Guellaen ◽  
Myriam Casanova ◽  
Colin Bishop ◽  
Danielle Geldwerth ◽  
Gabriel Andre ◽  
...  
Keyword(s):  
Single Copy ◽  
Dna Fragments ◽  
Xx Males ◽  
Copy Dna ◽  
Single Copy Dna

The Possible Common Origin of tRNA and 5S rRNA

1983 ◽  
Vol 38 (5-6) ◽  
pp. 501-504 ◽  
Author(s):  
Mária Ujhelyi
Keyword(s):  
Common Ancestor ◽  
Common Origin ◽  
5S Rrna ◽  
Mitochondrial Trna ◽  
Trna Molecule ◽  
The Common

Seryl tRNA (anticodon GCU) from mammalian mito­chondria shows in comparison to other mitochondrial tRNAs additional special features differing from the generalized tRNA model. When arranged in the tradi­tional cloverleaf form, eight bases fall within the TΨC loop, and the entire dihydrouridine loop is lacking. This seryl tRNA molecule is therefore shorter than other tRNAs. It was originally thought to represent a mito­chondrial analogon of 5 S rRNA and its precise classifica­tion is still disputed. The present studies suggest that this mitochondrial tRNA represents a fossil molecule which is related to the common ancestor of the present tRNA and 5 S rRNA molecules.

scholarly journals The replication machinery of LUCA: common origin of DNA replication and transcription

BMC Biology ◽  
2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Eugene V. Koonin ◽  
Mart Krupovic ◽  
Sonoko Ishino ◽  
Yoshizumi Ishino
Keyword(s):  
Dna Replication ◽  
Common Origin ◽  
Replication Machinery ◽  
Origin Of Dna Replication

The globalisation of knowledge: why trees become networks

foresight ◽  
2004 ◽  
Vol 6 (1) ◽  
pp. 10-12 ◽  
Author(s):  
João Caraça
Keyword(s):  
Common Origin ◽  
New Paradigm ◽  
The Times

Knowledge and the languages devised for its expression and circulation within communities evolve and drift with the times. The emergence of a new paradigm for technology, economy and society, based on information and knowledge, naturally brings along the need to rearrange and rethink our perception of how the diverse fields and disciplines are organised and classified, how they communicate and interact. A descriptive understanding of the realm of knowledge (as an “archipelago”) is discussed, enhancing its reticular character and its operation as a network that does not postulate any common origin or hierarchy. This metaphor is better adapted to map knowledge in a world of intensive communication and networking processes.

Common Origin of Enthalpic and Entropic Substituent Effects in Reactions of Benzhydryl Cations with Nucleophiles

1995 ◽  
Vol 34 (4) ◽  
pp. 490-492 ◽  
Author(s):  
Matthias Patz ◽  
Herbert Mayr ◽  
Jörg Bartl ◽  
Steen Steenken
Keyword(s):  
Substituent Effects ◽  
Common Origin
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