[GENOMIC VARIABILITY DURING PREGNANCY TRIMESTERS]

Area of Science:

• Genetics
• Reproductive Biology
• Cellular Biology

Background:

• Understanding genome stability during pregnancy is crucial for monitoring fetal development and maternal health.
• Previous studies have indicated potential genomic changes during gestation, but trimester-specific variations require further elucidation.

Purpose of the Study:

• To investigate the trimester-specific functional variability of genome stability and ribosomal cistone activation in pregnant women.
• To compare genomic parameters between different pregnancy trimesters and healthy non-pregnant women.

Main Methods:

• Analysis of chromosomal aberrations and fragile sites frequencies across trimesters.
• Assessment of ribosomal cistone activation through Nucleolar organizing regions (NORs) and acrocentric chromosome associations.
• Comparison with control groups of non-pregnant healthy women.

Main Results:

• Genome stability, measured by chromosomal aberrations and fragile sites, did not significantly differ from non-pregnant controls, except for a higher frequency of fragile sites in the first trimester.
• Specific genomic variations observed include deheterochromatization and heterochromatinization patterns.
• Increased activity of the protein-synthesizing apparatus was indicated by elevated NORs activation and acrocentric chromosome associations in all trimesters, with a significant increase in the third trimester.

Conclusions:

• Pregnancy maintains overall genome stability, with the first trimester showing a unique characteristic of increased fragile site frequency.
• Elevated protein synthesis activity is a consistent feature throughout pregnancy, suggesting adaptation to increased metabolic demands.
• Trimester-specific genomic modifications may occur, particularly concerning acrocentric chromosome associations in the third trimester.