Intraindividual Y-chromosome heteromorphism

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.

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Does the Y-chromosome facilitate sexual dimorphic evolution in insects or constrain autosomal evolution?

10.1603/ice.2016.114943 ◽

2016 ◽

Author(s):

Ian C Kutch

Keyword(s):

Y Chromosome

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Detection Y Chromosome Microdeletions Among Iraq Population in Infertile Patients with Azoospermia and Severe Oligospermia

International Journal of Drug Delivery Technology ◽

10.25258/ijddt.9.2.23 ◽

2019 ◽

Vol 9 (02) ◽

Author(s):

Samah A Hammood ◽

Alaauldeen S M AL-Sallami ◽

Saleh M Al-Khafaji

Keyword(s):

Y Chromosome ◽

Karyotype Analysis ◽

Semen Analysis ◽

Obstructive Azoospermia ◽

Severe Oligozoospermia ◽

Infertile Men ◽

Y Chromosome Microdeletions ◽

Detailed Evaluation ◽

Health Organization ◽

Infertile Patients

Objective: To detection of microdeletions of Y chromosome and study the frequency of microdeletions in infertile men with non-obstructive azoospermia or severe oligozoospermia(Middle Euphrates center)in Iraq population. Material and methods: 153 males were included in the study, the casesweredivided into groups according to the infertility etiology and semen analysis according to Word health organization, the frequencies and the characteristicsof Y chromosome microdeletions were investigated in groups. Multiplex PCR was applied to detect the microdeletions. Results:Y chromosome microdeletion was detected in 42 (40.7%) of 153 cases ,Microdeletions in azoospermia showed more frequently detected 28 (52.8%), followed by severe oligospermia 14 (28 %),Microdeletions in the AZFc region were the most common 12 (22.64%), followed by AZFb 11(20.75%) and AZFa 5(9.43%) in azoospermia compared to severe oligospermisAZFc 6 (12%) AZFb 4 (8 %) and AZFa 4 (8%). Conclusion: Y chromosome microdeletions were detected quite frequently in certain infertility subgroups. Therefore, detailed evaluation of an infertile man by physical examination, semen analysis, hormonal evaluationsand when required, karyotype analysis may predict the patients for whom Y chromosome microdeletionanalysis is necessary and also prevent cost increases. Recommendation: This study emphasizes that analysis of microdeletions should be carried out for all patients with idiopathic azoospermia and severe oligospermia who are candidates for intracytoplasmic sperm injection

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