Centromere Repositioning in Cattle (Bos taurus) Chromosome 17

Area of Science:

• Genetics
• Cytogenetics
• Animal Breeding

Background:

• Centromeres are crucial for genome integrity during cell division in eukaryotes.
• A routine cytogenetic analysis was performed on a young Marchigiana bull for reproduction center entry.

Purpose of the Study:

• To investigate an unusual biarmed chromosome observed in a seemingly normal bull.
• To characterize the nature of the chromosomal abnormality and rule out common rearrangements.

Main Methods:

• Karyotyping and Fluorescence In Situ Hybridization (FISH) were used to analyze the chromosome structure.
• C-banding, array Comparative Genomic Hybridization (aCGH), and Single Nucleotide Polymorphism (SNP) arrays were employed for detailed genomic assessment.

Main Results:

• An abnormal biarmed chromosome was identified, with FISH confirming centromere repositioning on Bovine Chromosome 17 (BTA17).
• Pericentric inversion, reciprocal translocation, large deletions, and telomere presence were excluded.
• Satellite DNA remained in an acrocentric position, and the primary constriction was C-band negative.

Conclusions:

• This is the first documented instance of centromere repositioning in cattle.
• The identified chromosomal abnormality did not result in a large genomic deletion, suggesting potential mechanisms for centromere plasticity.