THE G AND Q BANDING PATTERN OF ELLOBIUS LUTESCENS. A UNIQUE CASE OF SEX DETERMINATION IN MAMMALS

1976 ◽  
Vol 18 (3) ◽  
pp. 497-502 ◽  
Author(s):  
Luis M. de la Maza ◽  
Jeffrey R. Sawyer

The karyotype of the microtine Ellobius lutescens Th., was analyzed using the G and Q banding techniques. One of the chromosomes of the first pair has the same bands in both sexes while the other member of the pair is unique to each sex. We propose that the sex determining mechanism of Ellobius lutescens is located in these chromosomes. The genetic burden imposed on this species due to this constitution is discussed.

2021 ◽  
Vol 14 (3) ◽  
pp. e240576
Author(s):  
Bilal Athar Jalil ◽  
Mohsin Ijaz ◽  
Amir Maqbul Khan ◽  
Thomas Glenn Ledbetter

COVID-19 has now emerged from a respiratory illness to a systemic viral illness with multisystem involvement. There is still a lot to learn about this illness as new disease associations with COVID-19 emerge consistently. We present a unique case of a neurological manifestation of a patient with structural brain disease who was COVID-19 positive and developed mental status changes, new-onset seizures and findings suggestive of viral meningitis on lumbar puncture. We also review the literature and discuss our case in the context of the other cases reported. We highlight the value of considering seizures and encephalopathy as one of the presenting features of COVID-19 disease.


In this paper an extensive study is reported of the very remarkable, and thus far apparently unique, case of the deformation in three dimensions of protocatechuic acid, to which attention was drawn many years ago by Otto Lehmann. The deformations are spontaneous, and are probably due to progressive gliding of the lattice planes, which exist in two configurations, one stable and the other unstable, the latter being the condition of the long prismatic rods when they first form. Such a prism presently deforms into a zigzag crystal, with stable and unstable sections in alternation which, with continuation of the deformation, becomes again straight, but now in the stable configuration. The bending is progressive, like that of an umbrella case, pendant from the end of an oblique cane pointed down, when the latter is pushed into it. The movements are so rapid that motion pictures, made with a microscope, were necessary for the observation of certain stages of the deformation. The deformations have been shown to many chemists and physicists during the past decade or more, none of whom had ever seen or heard of this remarkable type of crystal movement. The deformations are usually observed as the warm saturated solution cools, but they also occur after the crystal has been dried for many hours.


1972 ◽  
Vol 14 (1) ◽  
pp. 175-180 ◽  
Author(s):  
D. N. Singh

A dioecious grass Sohnsia filifolia (Fourn.) Airy Shaw (Syn. Calamochloa filifolia Fourn.) from Mexico has been found to have 2n = 20 chromosomes in both male and female plants. The staminate plants have one chromosome much longer than the other chromosomes of the complement. One pistillate plant was found to have 30 chromosomes, among which the largest chromosome is quite similar to the largest component of the diploid male plant. The longest chromosome has been designated as the Y chromosome. An XY-mechanism of the Drosophilia type has been suggested for the sex determination system in this species. One small supernumerary chromosome was observed in the microsporocytes of some male plants, but was absent in roots.


2007 ◽  
Vol 17 (1) ◽  
pp. 98-108
Author(s):  
Tom Bishop

Beckett represents a unique case of bilingual writing, not only because he self-translated (or self-adapted) his writing in the other language, but also because, as of the time he decided to write in French (and after having written only in French for some ten years) he uses both languages as language of first composition for the remainder of his life. In Beckett, there is not just a double creation but in fact a quadruple creation. We view the period of and the reasons for this initial change and then examine and illustrate the singularities of these four variables in Beckett's work.


1983 ◽  
Vol 25 (3) ◽  
pp. 210-214 ◽  
Author(s):  
J. Dvořák

Triticum aestivum chromosome "4A" is, like the B genome chromosomes, extensively heterochromatic while the remaining six A genome chromosomes are not. In the presence of the Ph gene it does not pair with any chromosome of einkorn wheats, T. monococcum and T. urartu, the source of the A genome. It is shown here that the same chromosome is also present in T. timopheevii which represents the other evolutionary lineage of wheats. The "4A" chromosomes of T. timopheevii and T. aestivum pair poorly with each other, like the B genome chromosomes of the two lineages, while the remaining A genome chromosomes, except for one arm, pair relatively well. Hence, in both lineages chromosome "4A" has the attributes of the B genome chromosomes, not of the A genome chromosomes. The C-banding pattern of chromosome "4A" of T. aestivum and T. timopheevii closely resembles the C-banding pattern of a chromosome of T. speltoides and less closely chromosome 4B1 of T. sharonense. On the basis of this and other evidence it is concluded that this chromosome was contributed by a species of the section Sitopsis and, consequently, belongs to the B genome. Additionally, there is evidence that the chromosome that was originally designated "4B" belongs to the A genome.


1956 ◽  
Vol 34 (2) ◽  
pp. 261-268 ◽  
Author(s):  
Áskell Löve ◽  
Nina Sarkar

The western North American dioecious species Rumex paucifolius is shown to be a tetraploid with 2n = 28 chromosomes. It is the third tetraploid known within the subgenus Acetosa, and the first polyploid dioecious taxon of that group, the others having either 2n = 14 ♂, 15 ♀ (R. Acetosa and relatives), or 2n = 8 ♂, 9 ♀ (R. hastatulus). The sex chromosomes of R. paucifolius are of the XX:XY type, the male sex being heterogametic. The X is a large chromosome, while the Y is the smallest chromosome of the complement. The mechanism of sex determination of R. paucifolius follows the Melandrium–Acetosella scheme with strongly epistatic male determinants in the Y–chromosome. Other dioecious Acetosae follow the Drosophila–Acetosa scheme of sex determination with a balance between the number of X and autosome complements, the Y being sexually inert. It is concluded from the observed cytogenetical and morphological differences that R. paucifolius should constitute a section of its own, Paucifoliae, which should be placed as far as possible from the section Acetosa, though within the same subgenus. The other American dioecious endemic, R. hastatulus, is placed in a subsection of the section Acetosa.


1992 ◽  
Vol 59 (3) ◽  
pp. 189-198 ◽  
Author(s):  
Miguel Torres ◽  
Lucas Sanchez

SummaryIn Drosophila, sex is determined by the relative number of X chromosomes to autosomal sets (X: A ratio). The amount of products from several X-linked genes, called sisterless elements, is used to indicate to Sex-lethal the relative number of X chromosomes present in the cell. In response to the X: A signal, Sex-lethal is activated in females but remains inactive in males, being responsible for the control of both sex determination and dosage compensation. Here we find that the X-linked segmentation gene runt plays a role in this process. Reduced function of runt results in femalespecific lethality and sexual transformation of XX animals that are heterozygous for Sxl or sis loss-of-function mutations. These interactions are suppressed by SxlMI, a mutation that constitutively expresses female Sex-lethal functions, and occur at the time when the X: A signal determines Sex-lethal activity. Moreover, the presence of a loss-of-function runt mutation masculinizes triploid intersexes. On the other hand, runt duplications cause a reduction in male viability by ectopic activation of Sex-lethal. We conclude that runt is needed for the initial step of Sex-lethal activation, but does not have a major role as an X-counting element.


2018 ◽  
Vol 8 (2) ◽  
pp. 141-162
Author(s):  
Bayyinatul Muchtaromah

In many verses of al-Qur'an, men are called to pay their attention to understand how they were created. Human creation and incredible aspects followed were strongly mentioned in many verses in detail until it's impossible for anyone who lived in the seventh century to recognize it. One of them was the information saying that the determinant of baby gender is the spermatozoa coming from men sperm. Allah said in his verse: "and that He (Allah) creates in pairs, male and female. From Nutfah (drops of semen male and female discharge) when it is emitted" (translation of al-Qur'an 53 verse 45-46). Branches of knowledge which have developed, such as Genetics and Molecular Biology, have proved scientifically the information accuracy which has been given by al-Qur'an. Nowadays it has been well-known that sex determination is determined by sperm of man and in fact women play no roles in this determination. If the ovum fuses with sperm which carries Y chromosome than the baby will be born as a male. Conversely, if the sperm carries X chromosome than the baby will be a female. In the other word, the sex of the baby is determined by the kind of man's sperm chromosome which fuses with women's ovum.


2013 ◽  
Vol 38 (4) ◽  
pp. 557-578 ◽  
Author(s):  
Daphne Jeyapal

Abstract. Beginning in mid-2008, the Tamil diaspora around the world organized in extraordinary activism against the escalating violence in northern Sri Lanka. Responses to the 2009 Tamil diaspora protests in Canada provide a unique case study to examine a contemporary moment of resistance, when race thinking and spatiality intersected within and beyond national borders. Using critical theories of representation, I conceptualize Canadian print media coverage of the protests as representations of a “strange encounter” with the other. I explore the media’s production of the other and its conflation of the Tamil protester-terrorist through constructions of space. I also examine how scale operates through underlying national values to conceptualize a precarious structure of belonging. Through these discursive moves, I demonstrate how the resulting figure of the “other,” the “outlaw,” and the “outsider” came to represent and delegitimize the racialized/ spatialized Tamil protest(er).


Crustaceana ◽  
1996 ◽  
Vol 69 (4) ◽  
pp. 455-475 ◽  
Author(s):  
Giovanna Vitagliano ◽  
Enzo Marchetti ◽  
Eleonora Vitagliano

AbstractFor the great majority of the amphipods and isopods a biased sex ratio is attributed to photoperiod or to micro-organisms present in the cytoplasm of the oocytes. Since monogenous pairs are found in orders and species phylogenetically very far from each other, in order to try and clarify this phenomenon, two geographical populations of Asellus aquaticus (Isopoda) were collected in the Netherlands and in Italy, where the duration of the cold season and the photoperiods are very different. From these parental (P) populations, 200 females and 200 males per population were randomly subsampled and bred under standard conditions of temperature and nutrition. One half of each P generation was subjected to 18 hours light per day, the other to 14 hours light per day. New-born of each pair (laboratory F1) were grown up to differentiation of external sexual characters under the same photoperiod experienced by the parents. Also, hybrid F1 generation, born from mating between the two populations, was conceived in both photoperiods, but, after birth, one half of the new-born was maintained in the same photoperiod in which they were conceived, the other half was grown under the other photoperiod. No significant difference between the sex ratios was found in the two photoperiods, neither between Italian nor between Dutch Asellus. The sex ratio of Dutch F1 is female biased, while it is male biased in Italian Asellus. The female- or male-biased sex ratio can be ascribed to the high proportion of monogenous pairs in which offspring sex ratio is significantly biased towards females (in the Dutch population) and/or in which offspring sex ratio is significantly biased towards males (in the Italian population). On the basis of these results we can rule out the influence of photoperiod in sex determination for this species. The results shown by the hybrids suggest some form of maternal inheritance. In fact, the hybrids' sex ratio as indeed the frequency of pairs breeding one sex alone, was skewed towards the same sex for which the maternal population showed a bias. We therefore consider the possibility of sex determination associated with a cytoplasmic factor (a mitochondrial DNA?), which would inactivate only one of the two sets of genes governing sex determination.


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