Cloacal anatomy and sex determination in Tiliqua sp.

Herpetological Bulletin ◽

10.33256/hb156.1113 ◽

2021 ◽

pp. 11-13

Author(s):

Filippo Spadola

Keyword(s):

Sex Determination ◽

Single Pair ◽

Irian Jaya ◽

Rigid Endoscope

A rigid endoscope was used to examine the cloacae of an adult pair of Tiliqua gigas gigas, and single specimens of Tiliqua gigas evanescens and Tiliqua sp. (Irian Jaya form). Throughout the procedure the animals showed no signs of stress. Clear anatomical differences were observed between the sexes. Females presented the typical two pairs of papillae (ureteral and genital) and males a single pair of urogenital papillae. The observed differences were confirmed when both pairs bred successfully in the following year.

Download Full-text

Sex determination

AccessScience ◽

10.1036/1097-8542.617400 ◽

2015 ◽

Keyword(s):

Sex Determination

Download Full-text

Sex determination banned in India

Nature ◽

10.1038/379201e0 ◽

1996 ◽

Vol 379 (6562) ◽

pp. 201-201

Keyword(s):

Sex Determination

Download Full-text

Sex determination and Y chromosome constitutive heterochromatin

Current Research in Biochemistry and Molecular Biology ◽

10.33702/crbmb.2019.1.1.1 ◽

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.

Download Full-text