Robertsonian translocation, pericentric inversion and heterochromatin block in the evolution of the Tailless Fruit Bat

1984 ◽  
Vol 40 (8) ◽  
pp. 875-876 ◽  
Author(s):  
H. S. Yong
Keyword(s):  
Pericentric Inversion ◽  
Robertsonian Translocation ◽  
Fruit Bat ◽  
Heterochromatin Block

Sex determination and Y chromosome constitutive heterochromatin

2019 ◽  
Vol 1 (1) ◽  
pp. 1-5
Author(s):  
Abyt Ibraimov
Keyword(s):  
Sex Determination ◽  
Y Chromosome ◽  
Constitutive Heterochromatin ◽  
Sex Differentiation ◽  
Secondary Sexual Characteristics ◽  
Biological Meaning ◽  
Heterochromatin Block ◽  
Sexual Characteristics ◽  
Open Question ◽  
Efficient Elimination

In many animals, including us, the genetic sex is determined at fertilization by sex chromosomes. Seemingly, the sex determination (SD) in human and animals is determined by the amount of constitutive heterochromatin on Y chromosome via cell thermoregulation. It is assumed the medulla and cortex tissue cells in the undifferentiated embryonic gonads (UEG) differ in vulnerability to the increase of the intracellular temperature. If the amount of the Y chromosome constitutive heterochromatin is enough for efficient elimination of heat difference between the nucleus and cytoplasm in rapidly growing UEG cells the medulla tissue survives. Otherwise it doomed to degeneration and a cortex tissue will remain in the UEG. Regardless of whether our assumption is true or not, it remains an open question why on Y chromosome there is a large constitutive heterochromatin block? What is its biological meaning? Does it relate to sex determination, sex differentiation and development of secondary sexual characteristics? If so, what is its mechanism: chemical or physical? There is no scientifically sound answer to these questions.

scholarly journals Molecular Analysis of Nondisjunction in Mice Heterozygous for a Robertsonian Translocation

Genetics ◽  
2002 ◽  
Vol 161 (3) ◽  
pp. 1219-1224
Author(s):  
Lara A Underkoffler ◽  
Laura E Mitchell ◽  
A Russell Localio ◽  
Shannon M Marchegiani ◽  
Justin Morabito ◽  
...  
Keyword(s):  
Molecular Analysis ◽  
Robertsonian Translocation ◽  
Metacentric Chromosome ◽  
Paternal Age ◽  
Chromosome 7 ◽  
Parental Origin ◽  
Molecular Genotyping ◽  
Factors Influencing ◽  
Meiotic Nondisjunction ◽  
Acrocentric Chromosomes

Abstract A Robertsonian translocation results in a metacentric chromosome produced by the fusion of two acrocentric chromosomes. Rb heterozygous mice frequently generate aneuploid gametes and embryos, providing a good model for studying meiotic nondisjunction. We intercrossed mice heterozygous for a (7.18) Robertsonian translocation and performed molecular genotyping of 1812 embryos from 364 litters with known parental origin, strain, and age. Nondisjunction events were scored and factors influencing the frequency of nondisjunction involving chromosomes 7 and 18 were examined. We concluded the following: The frequency of nondisjunction among 1784 embryos (3568 meioses) was 15.9%.Nondisjunction events were distributed nonrandomly among progeny. This was inferred from the distribution of the frequency of trisomics and uniparental disomics (UPDs) among all litters.There was no evidence to show an effect of maternal or paternal age on the frequency of nondisjunction.Strain background did not play an appreciable role in nondisjunction frequency.The frequency of nondisjunction for chromosome 18 was significantly higher than that for chromosome 7 in males.The frequency of nondisjunction for chromosome 7 was significantly higher in females than in males. These results show that molecular genotyping provides a valuable tool for understanding factors influencing meiotic nondisjunction in mammals.

scholarly journals Chromosomal Analysis in Crotophaga ani (Aves, Cuculiformes) Reveals Extensive Genomic Reorganization and an Unusual Z-Autosome Robertsonian Translocation

Cells ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 4
Author(s):  
Rafael Kretschmer ◽  
Ricardo José Gunski ◽  
Analía del Valle Garnero ◽  
Thales Renato Ochotorena de Freitas ◽  
Gustavo Akira Toma ◽  
...  
Keyword(s):  
Robertsonian Translocation ◽  
Chromosome Evolution ◽  
Sex Chromosome ◽  
Rare Event ◽  
Chromosome Morphology ◽  
Z Chromosome ◽  
Molecular Cytogenetic ◽  
Intrachromosomal Rearrangements ◽  
Genomic Reorganization

Although cytogenetics studies in cuckoos (Aves, Cuculiformes) have demonstrated an interesting karyotype variation, such as variations in the chromosome morphology and diploid number, their chromosome organization and evolution, and relation with other birds are poorly understood. Hence, we combined conventional and molecular cytogenetic approaches to investigate chromosome homologies between chicken and the smooth-billed ani (Crotophaga ani). Our results demonstrate extensive chromosome reorganization in C. ani, with interchromosomal rearrangements involving macro and microchromosomes. Intrachromosomal rearrangements were observed in some macrochromosomes, including the Z chromosome. The most evolutionary notable finding was a Robertsonian translocation between the microchromosome 17 and the Z chromosome, a rare event in birds. Additionally, the simple short repeats (SSRs) tested here were preferentially accumulated in the microchromosomes and in the Z and W chromosomes, showing no relationship with the constitutive heterochromatin regions, except in the W chromosome. Taken together, our results suggest that the avian sex chromosome is more complex than previously postulated and revealed the role of microchromosomes in the avian sex chromosome evolution, especially cuckoos.

scholarly journals Robertsonian Translocation [56,XX and 57,XY,rob(1;29)] in Captive Thai Gaur (Bos gaurus readei) by Conventional, GTG-Banding, CBG-Banding and Ag-NOR Banding Techniques

CYTOLOGIA ◽  
2011 ◽  
Vol 76 (1) ◽  
pp. 99-108 ◽  
Author(s):  
Alongklod Tanomtong ◽  
Wanpen Kakampuy ◽  
Suteera Suntararak ◽  
Kuntida Thammarat ◽  
Sarawut Kaewsri ◽  
...  
Keyword(s):  
Robertsonian Translocation ◽  
Bos Gaurus

scholarly journals Fertility problems in males carrying an inversion of chromosome 10

Open Medicine ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. 316-321
Author(s):  
Xinyue Zhang ◽  
Qingyang Shi ◽  
Yanhong Liu ◽  
Yuting Jiang ◽  
Xiao Yang ◽  
...  
Keyword(s):  
Spontaneous Abortion ◽  
Pericentric Inversion ◽  
Paracentric Inversion ◽  
Chromosome 10 ◽  
Partial Duplication ◽  
Recurrent Miscarriages ◽  
First Case ◽  
Fertility Problems ◽  
Male Carriers ◽  
Male Carrier

Abstract Chromosomal inversion is closely related to male infertility. Inversion carriers may produce abnormal gametes, which may lead to partial duplication/deletion of the embryonic chromosome and result in spontaneous abortion, a fetus with multiple anomalies, or birth of a malformed child. Genetic counselling remains challenging for these carriers in clinical practice. We report two male carriers with inversion of chromosome 10 and review 26 reported cases. In the first case, 46,XX,inv(10)(p13q22) of the fetal chromosome was found in prenatal diagnosis; this was inherited from the paternal side with 46XY,inv(10)(p13q22). Another case was a male carrier with inv(10)(q21.2q22.1). There have been 25 (89.3%) cases of pericentric inversion and three (10.7%) cases of paracentric inversion involving chromosome 10. Of 28 cases, nine were associated with pregestational infertility of the couples, while the other 19 cases were associated with gestational infertility of the couples or normozoospermia. The breakpoints at 10p15, 10p11, 10q11, and 10q21 were associated with pregestational infertility of the couples. The breakpoints at 10p15, 10p14, 10p13, 10p12, 10p11, 10q11, 10q21, 10q22, 10q23, 10q24, 10q25, and 10q26 were related to gestational infertility of the couples or normozoospermia. Although there is a high risk of infertility or recurrent miscarriages, carriers with inversion of chromosome 10 might produce healthy offspring. Natural pregnancy can be used as a choice for inversion carriers with recurrent spontaneous abortion.

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