An examination of chromosomes in the stallion (&lt;i&gt;Equus caballus&lt;/i&gt;) during meiosis

Scott, Ian; Long, Susan E.

doi:10.1159/000131415

Cited by 13 publications

(9 citation statements)

References 10 publications

(13 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our results are consistent with previous studies indicating the terminal associations between the distal segment of the acrocentric Y and the short arm of the submetacentric X chromosome to form the pseudoautosomal region in the horse (Scott and Long 1980; Power et al 1992). However, our study provides critical insight into the frequency and chromosomal distribution of recombination events in the equine species.…”

Section: Discussionsupporting

confidence: 94%

“…Pioneering studies used air-dried chromosomal spreads to describe the meiotic chromosomes of equine interspecific hybrids as well as the number of chiasmata during normal meiosis in the stallion (Chandley et al 1974; Scott and Long 1980). A subsequent study used electron microscopy for the analysis of synaptic abnormalities in a horse carrying an autosomal trisomy (Power et al 1992).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Chromatin configuration and epigenetic landscape at the sex chromosome bivalent during equine spermatogenesis

et al. 2011

View full text Add to dashboard Cite

Pairing of the sex chromosomes during mammalian meiosis is characterized by the formation of a unique heterochromatin structure at the XY body. The mechanisms underlying the formation of NIH Public Access Author ManuscriptChromosoma. Author manuscript; available in PMC 2012 June 1. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript this nuclear domain are reportedly highly conserved from marsupials to mammals. In this study, we demonstrate that in contrast to all eutherian species studied to date, partial synapsis of the heterologous sex chromosomes during pachytene stage in the horse is not associated with the formation of a typical macrochromatin domain at the XY body. While phosphorylated histone H2AX (γH2AX) and macroH2A1.2 are present as a diffuse signal over the entire macrochromatin domain in mouse pachytene spermatocytes, γH2AX, macroH2A1.2, and the cohesin subunit SMC3 are preferentially enriched at meiotic sex chromosome cores in equine spermatocytes. Moreover, although several histone modifications associated with this nuclear domain in the mouse such as H3K4me2 and ubH2A are conspicuously absent in the equine XY body, prominent RNA polymerase II foci persist at the sex chromosomes. Thus, the localization of key marker proteins and histone modifications associated with the XY body in the horse differs significantly from all other mammalian systems described. These results demonstrate that the epigenetic landscape and heterochromatinization of the equine XY body might be regulated by alternative mechanisms and that some features of XY body formation may be evolutionary divergent in the domestic horse. We propose equine spermatogenesis as a unique model system for the study of the regulatory networks leading to the epigenetic control of gene expression during XY body formation.

show abstract

Section: Discussionsupporting

confidence: 94%

Section: Discussionmentioning

confidence: 99%

Chromatin configuration and epigenetic landscape at the sex chromosome bivalent during equine spermatogenesis

et al. 2011

View full text Add to dashboard Cite

show abstract

“…In male horses the mean frequency of chiasmata per nucleus reported in this study was 50.45 ± 2.07, which is less than reported by Scott and Long [1980] (54.40 ± 1.80 per cell). These differences could be attributed to several factors, such as different stallions, methodology, and research groups.…”

Section: Chiasmata Frequency and Distribution In All Chromosomescontrasting

confidence: 82%

Male Horse Meiosis: Metaphase I Chromosome Configuration and Chiasmata Distribution

Al-Jaru

Goodwin

Skidmore³

et al. 2014

Cytogenet Genome Res

View full text Add to dashboard Cite

Chromosome configurations and chiasma frequency during the metaphase I stage of spermatogenesis in the male horse are characterized in this work. The genome-wide frequency and distribution of chiasmata was detected as 49.45 ± 2.07 for 14 fertile stallions. All X and Y chromosomes shared a single chiasma at their pseudoautosomal region, while 1-4 chiasmata were observed in autosomal chromosomes. The chiasma frequency and distribution were further studied for 8 different bivalents identified by FISH in 5 fertile stallions. Genetic length was calculated from chiasmata data for the whole genome as well as for these 8 chromosomes. The findings complement the genetic linkage data and provide insight into the genetic basis of spermatogenesis in normal stallions.

show abstract

“…In at least some species the male recombination rate is considerably less than that in females (Morton 1991;Ellegren et al 1994), but this might not be a ubiquitous phenomenon among mammals as suggested by data for cattle and sheep (Crawford et al 1995;Barendse et al 1997). The only clue to the genetic length of the equine genome comes from the analysis of meiotic chromosomes (Scott and Long 1980). The number of per cell chiasma in late diplotene or diakinesis among stallions was counted to 54.4 ‫ע‬ 1.8, which is comparable to that found in sheep (Chapman and Bruere 1977;Long 1978), but is higher than that in pig (Burt and Bell 1987), cattle, and goat (Logue 1977).…”

Section: Discussionmentioning

confidence: 74%

A Primary Male Autosomal Linkage Map of the Horse Genome

Lindgren¹,

Sandberg²,

Persson³

et al. 1998

Genome Res.

View full text Add to dashboard Cite

A primary male autosomal linkage map of the domestic horse (Equus caballus) has been developed by segregation analysis of 140 genetic markers within eight half-sib families. The family material comprised four Standardbred trotters and four Icelandic horses, with a total of 263 offspring. The marker set included 121 microsatellite markers, eight protein polymorphisms, five RFLPs, three blood group polymorphisms, two PCR–RFLPs, and one single strand conformation polymorphism (SSCP). One hundred markers were arranged into 25 linkage groups, 22 of which could be assigned physically to 18 different chromosomes (ECA1, ECA2, ECA3, ECA4, ECA5, ECA6, ECA7, ECA9, ECA10, ECA11, ECA13, ECA15, ECA16, ECA18, ECA19, ECA21, ECA22, and ECA30). The average distance between linked markers was 12.6 cM and the longest linkage group measured 103 cM. The total map distance contained within linkage groups was 679 cM. If the distances covered outside the ends of linkage groups and by unlinked markers were included, it was estimated that the marker set covered at least 1500 cM, that is, at least 50% of the genome. A comparison of the relationship between genetic and physical distances in anchored linkage groups gave ratios of 0.5–0.8 cM per Mb of DNA. This would suggest that the total male recombinational distance in the horse is 2000 cM; this value is lower than that suggested by chiasma counts. The present map should provide an important framework for future genome mapping in the horse.

show abstract

An examination of chromosomes in the stallion (<i>Equus caballus</i>) during meiosis

Cited by 13 publications

References 10 publications

Chromatin configuration and epigenetic landscape at the sex chromosome bivalent during equine spermatogenesis

Chromatin configuration and epigenetic landscape at the sex chromosome bivalent during equine spermatogenesis

Male Horse Meiosis: Metaphase I Chromosome Configuration and Chiasmata Distribution

A Primary Male Autosomal Linkage Map of the Horse Genome

Contact Info

Product

Resources

About