scholarly journals Validation of Fetal Microchimerism after Pregnancy in the ovine using qPCR

2021 ◽  
Author(s):  
J Alison Brown ◽  
Erika S Niland ◽  
Natalie L Pierce ◽  
J Bret Taylor
Keyword(s):  
Sex Ratio ◽  
Potential Role ◽  
Soft Tissues ◽  
Tissue Sample ◽  
Maternal Circulation ◽  
Offspring Sex Ratio ◽  
Fetal Dna ◽  
Fetal Microchimerism ◽  
Offspring Sex ◽  
The Brain

Abstract Fetal microchimerism has been detected in maternal tissues of humans and rodents during and after pregnancy. Studies focusing on fetal DNA transfer to maternal tissues in domestic animals are limited, especially in sheep. Fetal ram DNA was observed in the maternal circulation during pregnancy, but it is not known if this chimerism persists in soft tissues after parturition. The objectives of this exploratory study were to: 1) determine if male fetal DNA is detectable in soft tissues of mature ewes after parturition and if so, determine if detection repeatability differed with lifetime offspring sex ratio and 2) determine if male fetal DNA was present in soft tissues of yearling (primiparous) ewes shortly after parturition. Eight mature (open, non-lactating) and 8 yearling (primiparous, periparturient) Rambouillet ewes were used. Mature ewes (5- to 7- years old) had given birth to primarily 82% males (n = 4) or 71% female (n = 4) over a lifetime. Yearling ewes had birthed either a singleton male (n = 4) or female (n = 4) lambs. DNA was extracted from 10 and 11 different soft tissues from the mature and yearling ewes, respectively. Real-time PCR (qPCR) was used to identify the presence of the SRY gene in each tissue sample. Male DNA was detected in the brain and liver from 1 mature open ewe that had given birth to 2 males and 6 females during her lifetime. In younger ewes that gave birth to a ram lamb, male DNA was observed in the thyroid of 1 ewe and the pancreas and brain of a second ewe. Male DNA was detected in the ovary of 1 ewe that had given birth to a female lamb. Based on these data, we suggest fetal microchimerism in soft maternal tissues is possible in sheep and may remain after pregnancy has ended. The detection repeatability of male fetal DNA was not associated with sex ratio of lifetime offspring. Male DNA was observed in maternal soft tissues collected shortly after parturition. The greater detection of fetal male DNA found in younger ewes shortly after parturition may be due to not having enough time for fetal DNA clearance to occur. Future studies are warranted to further study XY chimerism in maternal tissues of the ewe and its potential role in ovine physiology.

scholarly journals PSI-30 Identification of fetal microchimerism in older ewes using qPCR

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 256-257
Author(s):  
Hannah M Teague ◽  
Erika S Niland ◽  
Natalie L Pierce ◽  
J Bret Taylor ◽  
J Alison Brown
Keyword(s):  
Sex Ratio ◽  
Soft Tissues ◽  
Sry Gene ◽  
Maternal Circulation ◽  
Offspring Sex Ratio ◽  
Fetal Dna ◽  
Fetal Microchimerism ◽  
Offspring Sex ◽  
The Brain ◽  
Different Tissues

Abstract The presence of a male co-twin during pregnancy has been found to impact lifetime reproductive performance in the sibling ewe. XY chimerism, thought to originate from a male co-twin, has been observed in ewes, and may be associated with the rare development of freemartins. Fetal ram DNA has been observed in the maternal circulation during pregnancy, but it is unknown if this chimerism persists after parturition. The objective of this study was to determine if fetal male cells were present in soft tissues of older ewes and if so, does the occurrence differ with lifetime offspring sex ratio. Eight ewes approximately 7-years-old and having given birth to at least 71% female (n = 4) or 82% males (n = 4) were tested. DNA was extracted from 10 different tissues from each ewe (n = 80). In triplicate, real-time PCR (qPCR) was used to identify the presence of the SRY gene in each sample. Using the SRY primer pair, male DNA was identified in the brain (between 1.25 ng / µL and 125 pg / µL) and liver (between 125 and 12.5 pg / µL) from a ewe that had given birth to two males during her lifetime. If any additional male fetal DNA was present, it was below the detectable limits. In addition to giving birth to two males, this ewe was also born with two male co-siblings, thus the origin (sibling or offspring) of the male DNA is not known. These data suggest fetal cell transfer in sheep is possible and the frequency of fetal microchimerism is not associated with sex ratio of lifetime offspring.

Offspring sex ratio in moose Alces alces in relation to paternal age: an experiment

2004 ◽  
Vol 10 (1) ◽  
pp. 51-57 ◽  
Author(s):  
Bernt-Erik Sæther ◽  
Erling J. Solberg ◽  
Morten Heim ◽  
John E. Stacy ◽  
Kjetill S. Jakobsen ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Alces Alces ◽  
Paternal Age ◽  
Offspring Sex Ratio ◽  
Offspring Sex

Breeding system can affect the offspring sex ratio in Syrian hamsters

2011 ◽  
Vol 45 (1) ◽  
pp. 55-57 ◽  
Author(s):  
M O M Chelini ◽  
N L Souza ◽  
E Otta
Keyword(s):  
Sex Ratio ◽  
Breeding System ◽  
Offspring Sex Ratio ◽  
Syrian Hamsters ◽  
Offspring Sex

scholarly journals Is biasing offspring sex ratio adaptive? A test of Fisher's principle across multiple generations of a wild mammal in a fluctuating environment

2018 ◽  
Vol 285 (1891) ◽  
pp. 20181251 ◽  
Author(s):  
Andrea E. Wishart ◽  
Cory T. Williams ◽  
Andrew G. McAdam ◽  
Stan Boutin ◽  
Ben Dantzer ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Tamiasciurus Hudsonicus ◽  
Red Squirrels ◽  
Offspring Sex Ratio ◽  
Offspring Sex ◽  
Adult Sex Ratio ◽  
Secondary Sex Ratio ◽  
North American Red Squirrels ◽  
Negative Frequency Dependent Selection ◽  
Fisher’S Principle

Fisher's principle explains that population sex ratio in sexually reproducing organisms is maintained at 1 : 1 owing to negative frequency-dependent selection, such that individuals of the rare sex realize greater reproductive opportunity than individuals of the more common sex until equilibrium is reached. If biasing offspring sex ratio towards the rare sex is adaptive, individuals that do so should have more grandoffspring. In a wild population of North American red squirrels ( Tamiasciurus hudsonicus ) that experiences fluctuations in resource abundance and population density, we show that overall across 26 years, the secondary sex ratio was 1 : 1; however, stretches of years during which adult sex ratio was biased did not yield offspring sex ratios biased towards the rare sex. Females that had litters biased towards the rare sex did not have more grandoffspring. Critically, the adult sex ratio was not temporally autocorrelated across years, thus the population sex ratio experienced by parents was independent of the population sex ratio experienced by their offspring at their primiparity. Expected fitness benefits of biasing offspring sex ratio may be masked or negated by fluctuating environments across years, which limit the predictive value of the current sex ratio.

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