A High Incidence of Adjacent-1 Meiotic Segregation Pattern, Revealed by Multicolor Sperm FISH, in a Carrier Boar of a New Reciprocal Translocation t(6;16)(p13;q23)

Abstract

Reciprocal translocations pose a serious problem in pig breeding due to the reduced fertility of the carriers. This paper presents a new reciprocal translocation in a phenotypically normal, but hypoprolific (20% reduction) boar. Chromosome banding as well as the FISH technique with the use of BAC and telomeric probes was applied for a detailed characterization of this chromosome rearrangement. The karyotype of the studied boar was described as 38,XY,t(6;16)(p13;q23). The meiotic segregation of the quadrivalent was studied in 1,071 sperms by multicolor FISH. The most frequent segregation patterns were alternate (47.5%) and adjacent 1 (41.9%), while adjacent 2 and 3:1 were less frequent at 1.2 and 9.2%, respectively. Surprisingly, the frequency of the adjacent-1 segregation appeared to be relatively high, when compared with human and pig reciprocal translocations studied by sperm FISH. Our study, along with a review of the literature, shows that a reduction of fertility in the carriers and the incidence of different segregation patterns of the quadrivalent may vary within a broad range, and both aspects seem to be unrelated. A need for obligatory karyotype screening programs of artificial insemination boars is emphasized.

Meiotic pairing and gene expression disturbance in germ cells from an infertile boar with a balanced reciprocal autosome-autosome translocation

“…Sperm meiotic segregation studies performed in human carriers of balanced reciprocal translocations showed that 18.6–80.7 % of the spermatozoa were chromosomally unbalanced (Benet et al 2005; Morel et al 2004). Until now, sperm FISH meiotic segregation analyses for three reciprocal translocations have only been carried out in pigs (Kociucka et al 2014; Massip et al 2008; Pinton et al 2004). One of these translocations (t(3;15)) was characterized by a small derivative chromosome (comparable in size to the der(14) chromosome observed in the present study) and a high proportion of 3:1 meiotic products (Pinton et al 2004).…”

Boar Differences In Artificial Insemination Outcomes: Can They Be Minimized?

“…It is important to note that in vitro fertilizing ability and percentage of sperm with damaged nuclear DNA seem not to change substantially over time in healthy sires (Hallap et al 2005;Foxcroft et al 2008). The same applies for RT disorders (Kociucka et al 2014). Therefore, single assessments performed when young healthy boars become part of AI-centres could be enough to obtain meaningful estimates of in vivo fertility potential expected throughout the productive life of an otherwise healthy boar.…”

“…The same applies for RT disorders (Kociucka et al. ). Therefore, single assessments performed when young healthy boars become part of AI‐centres could be enough to obtain meaningful estimates of in vivo fertility potential expected throughout the productive life of an otherwise healthy boar.…”

Chromosome Abnormalities in Domestic Animals as Causes of Disorders of Sex Development or Impaired Fertility

“…Similarly to centric fusions, decreased fertility is caused by the abnormal segregation of a tetravalent during anaphase I. However, the proportion of chromosomally unbalanced gametes is much higher in carriers of reciprocal translocations and varies between 20 and 50% [67]. As a consequence, a large proportion of the embryos die at an early embryonic stage, and thus the decrease of fertility is much more pronounced.…”

“…G-banded karyotype of a boar carrier of reciprocal translocation -t(6;16)(p13;q23). For details, see Kociucka et al[67].…”