2 research outputs found
Al(OH)(3) facilitated synthesis of water-soluble, magnetic, radiolabelled and fluorescent hydroxyapatite nanoparticles
Magnetic and fluorescent hydroxyapatite nanoparticles were synthesised using Al(OH)3-stabilised MnFe2O4 or Fe3O4 nanoparticles as precursors. They were readily and efficiently radiolabelled with 18F. Bisphosphonate polyethylene glycol polymers were utilised to endow the nanoparticles with excellent colloidal stability in water and to incorporate cyclam for high affinity labelling with 64Cu
Young Genes out of the Male: an Insight from Evolutionary Age Analysis of the Pollen Transcriptome
The birth of new genes in genomes is an important evolutionary event. Several studies reveal that new genes in
animals tend to be preferentially expressed in male reproductive tissues such as testis (Betrán et al., 2002; Begun et al.,
2007; Dubruille et al., 2012), and thus an “out of the testis” hypothesis for the emergence of new genes has been
proposed (Vinckenbosch et al., 2006; Kaessmann, 2010). However, such phenomena have not been examined in plant
species. Here, by employing a phylostratigraphic method we dated the origin of protein coding genes in rice and
Arabidopsis thaliana and observed a number of young genes in both species. These young genes tend to encode short
extracellular proteins, which may be involved in rapid evolving processes, such as: reproductive barriers, species
specification and anti-microbial processes. Further analysis of transcriptome age indexes across different tissues
revealed that male reproductive cells express a phylogenetically younger transcriptome than other plant tissues.
Compared to sporophytic tissues, the young transcriptomes of the male gametophyte displayed greater complexity and
diversity, which included a higher ratio of anti-sense and inter-genic transcripts, reflecting pervasive transcription state
that facilitated the emergence of new genes. Here, we propose that pollen may act as an “innovation incubator” for the
birth of de novo genes. With cases of male-biased expression of young genes reported in animals, the “new genes out
of the male” model revealed a common evolutionary force that drives reproductive barriers, species specification and
the upgrading of defensive mechanisms against pathogens