The variety of sterility and gradual progression to fertility in hybrids of the horse and donkey

Zong, E; Fan, Guiyan

doi:10.1038/hdy.1989.54

Cited by 23 publications

(13 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The findings are of importance, not only because they may contribute to a fuller understanding of speciation, evolutionary biology and cell biology, but because they might also help us to understand why a gradual progression exists in mules and hinnies between those that show sterility and those that show partial or complete fertility (Zong & Fan, 1989).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

A genetic study of esterase activity in mules, hinnies and their backcross progeny

1992

Self Cite

View full text Add to dashboard Cite

Eight B1 progeny produced by backcrossing fertile female mules and hinmes with donkeys or horses, were assessed for levels of esterase isozyme in their sera. Four bands are found in horses, three fast moving (E3) and one slow (E1), while donkeys show only the slow E1 band. Mules and hinnies, the F1 hybrids of the horse and donkey, show both the E1 and E3 bands. Among the eight tested backcross (B1) progeny, a variety of different combinations are found, depending on whether or not the horse band (E3) has been trasmitted by the mule or hinny parent. The significance of this result is because it shows that irregular patterns of segregation of the horse and donkey chromosomes exist between different F1 hybrids, contrary to some hypotheses proposed previously.

show abstract

Section: Resultsmentioning

confidence: 99%

“…Esterase isozyme serum levels were recently tested in two backcross (B1) progeny from a fertile hinnyxjack donkey cross (Zong & Fan, 1989). One showed the presence of a fast moving E3 horse band (contributed by the hinny), the other did not.…”

Section: Introductionmentioning

confidence: 99%

A genetic study of esterase activity in mules, hinnies and their backcross progeny

1992

Self Cite

View full text Add to dashboard Cite

show abstract

“…One of them, PRDM9 (referred to as a speciation gene), is involved in the control of DSB formation10. Male sterility or reduced fertility accompanied by synaptic aberrations of autosomes and sex chromosomes has been widely reported in hybrids of chromosomally divergent mammalian species, subspecies and local populations3111213141516171819.…”

mentioning

confidence: 99%

Cytological basis of sterility in male and female hybrids between sibling species of grey voles Microtus arvalis and M. levis

Torgasheva

Borodin

2016

Sci Rep

View full text Add to dashboard Cite

To make insight into the cytological basis of reproductive isolation, we examined chromosome synapsis and recombination in sterile male and female hybrids between Microtus arvalis and M. levis. These sibling species differ by a series of chromosomal rearrangements (fusions, inversions, centromere shifts and heterochromatin insertions). We found that meiosis in male hybrids was arrested at leptotene with complete failure of chromosome pairing and DNA double-strand breaks repair. In the female hybrids meiosis proceeded to pachytene; however, the oocytes varied in the degree of pairing errors. Some of them demonstrated almost correct chromosome pairing, while most of them contained a varying number of univalents and multivalents with extensive regions of asynapsis and non-homologous synapsis. Variation between oocytes was probably caused by stochasticity in the ratio of homologous to non-homologous pairing initiations. We suggest that substantial chromosomal and genetic divergence between the parental species affects preliminary alignment of homologues, homology search and elimination of ectopic interhomologue interactions that are required for correct homologous pairing. Apparently, pairing failure in male and aberrant synapsis in female vole hybrids followed by meiotic silencing of unsynapsed chromatin cause apoptosis of gametocytes and sterility.

show abstract

“…If fertile balanced gametes capable of siring offspring occur in hybrids between species with different chromosome numbers (e.g. in mules and hinnies: Trujillo et al, 1969;Chandley et al, 1974, Rong et al, 1988Zong & Fan, 1989), it is generally not possible to predict accurately the karyotype of the backcross progeny for two reasons. First, balanced gametes may arise due to several meiotic configurations (Yang et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

“…homoploid backcross progeny) may arise when first-generation hybrids produce reduced gametes. Reduced gametes of hybrids between species with different chromosome numbers often have variable chromosome contents (Zong & Fan, 1989), because chromosomes unpaired during meiosis pass more or less randomly to one or other daughter cell (Maynard Smith, 1985). Many of the gametes produced by hybrids may therefore be aneuploid, with some chromosomes occurring twice and other chromosomes wholly absent.…”

Section: Introductionmentioning

confidence: 99%

Chromosome inheritance and reproductive barriers in backcrosses between two hybridizing Viviparus snail species

Sbilordo

Martin

Ribi³

2012

Journal of Molluscan Studies

View full text Add to dashboard Cite

Hybridization must be followed by repeated backcrossing of the subsequent hybrid generations to the parental species for gene exchange between species to occur. Due to meiotic failures, first-generation hybrids of some species produce unreduced gametes. Their progeny in backcrosses with a diploid parental species are polyploid and functionally sterile. Polyploidy of the backcross generation may therefore act as an instantaneous barrier to gene flow between hybrids and the parental species. Here we determined chromosome inheritance in backcrosses of two hybridizing freshwater caenogastropod snail species to assess whether gene introgression is inhibited in the first backcross generation. Viviparus ater and V. contectus intermate in nature and produce viable F1 hybrid progeny, although offspring sex ratio is strongly male biased. Despite the different chromosome numbers of the two parental species (V. ater, 2n ¼ 18; V. contectus, 2n ¼ 14), the F1 hybrids are able to reproduce. Allozyme data from natural populations are compatible with gene exchange between the two species, although there is also evidence suggesting that some alleles may be shared because of common ancestry. Our study revealed that all viable backcross progeny were homoploid as they inherited between seven and nine chromosomes from the hybrid father. The siring success of the karyotypically different hybrid sperm was skewed against one sperm karyotype depending on the non-hybrid mother in the cross. In backcross broods of V. ater females, the observed distribution of the karyotypes conformed with an assumption of random segregation of two unpaired chromosomes at meiosis in hybrid males. In contrast, when backcrossing hybrid males to V. contectus females, post-copulatory processes ultimately determined the karyotype distribution of the backcross progeny. Homoploidy of all backcross progeny together with the presence of sperm and embryos in their gonads makes gene exchange between the two parental species through hybridization possible.

show abstract

The variety of sterility and gradual progression to fertility in hybrids of the horse and donkey

Cited by 23 publications

References 17 publications

A genetic study of esterase activity in mules, hinnies and their backcross progeny

A genetic study of esterase activity in mules, hinnies and their backcross progeny

Cytological basis of sterility in male and female hybrids between sibling species of grey voles Microtus arvalis and M. levis

Chromosome inheritance and reproductive barriers in backcrosses between two hybridizing Viviparus snail species

Contact Info

Product

Resources

About