The Karyotype and Possible Sex Chromosomes of Ginkgo Biloba

Newcomer, Earl H.

doi:10.1002/j.1537-2197.1954.tb14375.x

Cited by 23 publications

(14 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Next generation sequencing of ITS pools revealed that the intragenomic diversity of rDNA units is higher in species with multiple chromosomal loci than in species with a single locus in Nicotiana (Matyasek et al , 2012). In this context, sex chromosomes in G. biloba (Newcomer, 1954) distinguished by number of satellites that likely represent rDNA loci, may generate some unit diversity. However, the Southern hybridisations do not support significant heterogeneity in the spectrum of rDNA families, and >90% of rDNAs seem to form a single or possibly two families.…”

Section: Discussionmentioning

confidence: 99%

Dancing together and separate again: gymnosperms exhibit frequent changes of fundamental 5S and 35S rRNA gene (rDNA) organisation

Garcia

Kovařı́k

2013

Heredity

View full text Add to dashboard Cite

In higher eukaryotes, the 5S rRNA genes occur in tandem units and are arranged either separately (S-type arrangement) or linked to other repeated genes, in most cases to rDNA locus encoding 18S–5.8S–26S genes (L-type arrangement). Here we used Southern blot hybridisation, PCR and sequencing approaches to analyse genomic organisation of rRNA genes in all large gymnosperm groups, including Coniferales, Ginkgoales, Gnetales and Cycadales. The data are provided for 27 species (21 genera). The 5S units linked to the 35S rDNA units occur in some but not all Gnetales, Coniferales and in Ginkgo (∼30% of the species analysed), while the remaining exhibit separate organisation. The linked 5S rRNA genes may occur as single-copy insertions or as short tandems embedded in the 26S–18S rDNA intergenic spacer (IGS). The 5S transcript may be encoded by the same (Ginkgo, Ephedra) or opposite (Podocarpus) DNA strand as the 18S–5.8S–26S genes. In addition, pseudogenised 5S copies were also found in some IGS types. Both L- and S-type units have been largely homogenised across the genomes. Phylogenetic relationships based on the comparison of 5S coding sequences suggest that the 5S genes independently inserted IGS at least three times in the course of gymnosperm evolution. Frequent transpositions and rearrangements of basic units indicate relatively relaxed selection pressures imposed on genomic organisation of 5S genes in plants.

show abstract

Section: Discussionmentioning

confidence: 99%

Dancing together and separate again: gymnosperms exhibit frequent changes of fundamental 5S and 35S rRNA gene (rDNA) organisation

Garcia

Kovařı́k

2013

Heredity

View full text Add to dashboard Cite

show abstract

“…Male and female Ginkgo plants have 22 autosomes and a pair of ZW sex chromosomes. Newcomer (109) was the first to recognize that the largest chromosomes are the sex chromosomes, and that they are dimorphic on the basis of their centromere positions, one metacentric and the other submetacentric. However, Newcomer thought G. biloba had male XY heterogamety.…”

Section: Gymnospermsmentioning

confidence: 99%

Sex Chromosomes in Land Plants

Ming

Bendahmane

Renner

2011

Annu. Rev. Plant Biol.

435

438

View full text Add to dashboard Cite

Sex chromosomes in land plants can evolve as a consequence of close linkage between the two sex determination genes with complementary dominance required to establish stable dioecious populations, and they are found in at least 48 species across 20 families. The sex chromosomes in hepatics, mosses, and gymnosperms are morphologically heteromorphic. In angiosperms, heteromorphic sex chromosomes are found in at least 19 species from 4 families, while homomorphic sex chromosomes occur in 20 species from 13 families. The prevalence of the XY system found in 44 out of 48 species may reflect the predominance of the evolutionary pathway from gynodioecy towards dioecy. All dioecious species have the potential to evolve sex chromosomes, and reversions back from dioecy to various forms of monoecy, gynodioecy, or androdioecy have also occurred. Such reversals may occur especially during the early stages of sex chromosome evolution before the lethality of the YY (or WW) genotype is established.

show abstract

“…The reproductive structures in Ginkgo have remained well preserved since the early Tertiary (Crane et al ., 1990; Zhou, 2009). Its sex differences are embodied in many aspects, including its karyotype (Newcomer, 1954), physiological characteristics (Crane et al ., 2013), and applications (Liao et al ., 2009). Transcriptome analysis has revealed that besides the fact that many genes involved in phytohormone signaling and DNA methylation are differentially expressed between the sexes (Du et al ., 2016), some MADS‐box, WUS, and CLV genes are differentially expressed in male and female reproductive tissues (Wang et al ., 2016).…”

Section: Introductionmentioning

confidence: 99%