Cytogenetic analysis of reciprocal hybrids and their parents between Larix leptolepis and Larix gmelinii: implications for identifying hybrids

Abstract

We studied the parental taxa and the interspecific reciprocal hybrids between Larix leptolepis with Larix gmelinii, using classical cytogenetic methods, as well as fluorescence in situ hybridization (FISH) and genomic in situ hybridization. A high frequency (>90%) of complete bivalent formation was observed in reciprocal hybrids. Less than 10% of pollen mother cells exhibited abnormalities. The most frequent abnormalities were bridges. Multivalent chromosome associations were also observed in both reciprocal hybrids, suggesting that some chromosome interchange events did occur, and introgressions from one to the other species were possible. Intergenomic recombination indicates that genes might be readily introgressed into one species from the other in the genus Larix. Interspecific hybridization may be a potential method for genetic improvement in larch. FISH markers documented that the recombinant genomes of reciprocal hybrids were strictly additive and stable, indicating that FISH also might be a useful tool in Larix breeding.

Karyotype evolution in the Pinaceae: implication with molecular phylogeny

“…Larix leptolepis and Larix decidua have similar karyotypes but can be distinguished from each other based on cytological markers related Pagination not final/Pagination non finale to the topography of a pair of chromosomes (Nkongolo and Klimaszewska 1995). Zhang et al (2010) used FISH localization of the 45S rDNA gene to differentiate Larix leptolepis and Larix gmelinii karyotypes and their hybrids. Larix leptolepis has two pairs of 45S rDNA signals, whereas Larix gmelinii had three pairs of 45S rDNA signals.…”

Comparative Repeat Profiling of Two Closely Related Conifers (Larix decidua and Larix kaempferi) Reveals High Genome Similarity With Only Few Fast-Evolving Satellite DNAs

“…Consistent with other Pinaceae species, all larches have 2 n = 2 x = 24 chromosomes with conserved sizes, divided into six meta- and six submetacentric chromosome pairs ( Hizume et al, 1993 ; Prunier et al, 2016 ). In larches, the 18S-5.8S-26S (35S) and 5S rDNAs are physically separated ( Garcia and Kovařík, 2013 ), and fluorescent in situ hybridization (FISH) with respective rDNA probes clearly mark three 35S and one 5S rDNA-labeled chromosome pairs for L. decidua ( Lubaretz et al, 1996 ) and two 35S and one 5S rDNA-labeled chromosome pairs for L. kaempferi ( Liu et al, 2006 ; Zhang et al, 2010 ). Similarly, a single satDNA family is known (“LPD”), marking a heterochromatic chromosomal band on 22 chromosomes in L. kaempferi ( Hizume et al, 2002 ).…”

Comparative repeat profiling of two closely related conifers (Larix decidua and Larix kaempferi) reveals high genome similarity with only few fast-evolving satellite DNAs

“…kaempferi (Liu et al, 2006;Zhang et al, 2010), respectively. Similarly, a single satDNA family is known ("LPD"), marking a heterochromatic chromosomal band on 22 chromosomes in L. kaempferi (Hizume et al, 2002).…”

“…Consistent with other Pinaceae species, all larches have 2n=2x=24 chromosomes with conserved sizes, divided into six meta- and six submetacentric chromosome pairs (Hizume et al, 1993; Prunier et al, 2016). In larches, the 18S-5.8S-25S and 5S rDNAs are physically separated (Garcia and Kovařík, 2013), and fluorescent in situ hybridization (FISH) with respective rDNA probes clearly mark three and one chromosome pair for L. decidua (Lubaretz et al, 1996) and two and one pair for L. kaempferi (Liu et al, 2006; Zhang et al, 2010), respectively. Similarly, a single satDNA family is known (“LPD”), marking a heterochromatic chromosomal band on 22 chromosomes in L. kaempferi (Hizume et al, 2002).…”