Y chromosome abnormalities are frequently associated with male infertility. Men with ring Y chromosomes can present with sexual infantilism, ambiguous genitalia, hypospadias, or azoospermia. AZF microdeletions can result in spermatogenic defects in such patients. Here, we report an unusual karyotype of 45,X/46,X,r(Y)/46,X,dic r(Y) in an azoospermic man. However, the reason for this patient's azoospermia is not an AZF microdeletion but might be the abnormal structure of the r(Y) chromosome, the 45,X cell line, mosaicism of the 3 cell lines, or another unknown cause. In such cases, if the couple wishes to reproduce, cytogenetic, molecular and fluorescent in situ hybridization evaluations should be performed, and preimplantation genetic diagnosis should be used together with assisted reproductive technology.

Lauraceae includes the genus Phoebe, and the family is linked to the evolution of magnoliids. We sequenced the genome of Phoebe bournei Nanmu. The assembled genome size was 989.19 Mb, with a contig N50 value of 2.05 Mb. A total of 28,198 protein-coding genes were annotated in P. bournei. Whole-genome duplication (WGD) analysis showed that Lauraceae has experienced two WGD events; the older WGD event occurred just before the divergence of Lauraceae and Magnoliales, and the more recent WGD was shared by all lineages of Lauraceae. The phylogenetic tree showed that magnoliids form a sister clade to monocots and eudicots. We also identified 63 MADS-box genes, including AGL12-like genes that may be related to the regulation of P. bournei roots and FIN219-like genes encoding GH3 proteins, which are involved in photomorphogenesis. SAUR50-like genes involved in light signal-mediated pedicel or stem development were also identified. Four ATMYB46-and three PtrEPSP-homologous genes related to lignin biosynthesis were identified. These genes may be associated with the formation of straight trunks in P. bournei. Overall, the P. bournei reference genome provides insight into the origin, evolution, and diversification of Phoebe and other magnoliids.

To improve our understanding of the origin and evolution of mycoheterotrophic plants, we here present the chromosome-scale genome assemblies of two sibling orchid species: partially mycoheterotrophic Platanthera zijinensis and holomycoheterotrophic Platanthera guangdongensis. Comparative analysis shows that mycoheterotrophy is associated with increased substitution rates and gene loss, and the deletion of most photoreceptor genes and auxin transporter genes might be linked to the unique phenotypes of fully mycoheterotrophic orchids. Conversely, trehalase genes that catalyse the conversion of trehalose into glucose have expanded in most sequenced orchids, in line with the fact that the germination of orchid non-endosperm seeds needs carbohydrates from fungi during the protocorm stage. We further show that the mature plant of P. guangdongensis, different from photosynthetic orchids, keeps expressing trehalase genes to hijack trehalose from fungi. Therefore, we propose that mycoheterotrophy in mature orchids is a continuation of the protocorm stage by sustaining the expression of trehalase genes. Our results shed light on the molecular mechanism underlying initial, partial and full mycoheterotrophy.

The 14-bp insertion/deletion (indel) polymorphism located in the 3' UTR of the human leukocyte antigen-G (HLA-G) gene plays a role in several autoimmune and chronic inflammatory diseases. HLA-G expression is associated with hepatocellular carcinoma (HCC) prognosis, especially in early stage, with high expression independently associated with shortened overall survival and increased tumor recurrence. In the present study, we carried out a case-control study in a Chinese population (318 cases and 599 controls) to estimate the susceptibility to HCC associated with the 14-bp indel polymorphism. Logistic regression analysis showed that the heterozygote and the homozygote 14-bp ins/ins confer a lower risk of HCC (adjusted OR = 0.75, 95% CI: 0.57-1.01, p = 0.061; OR = 0.54, 95% CI: 0.30-0.98, p = 0.031, respectively). Hepatitis B virus (HBV) stratification analysis showed that the associations were stronger in the HBV-positive population. Immunohistochemical analysis further showed that HLA-G expression in HCC tissues with 14-bp del/del genotype was more prominent than for heterozygous and 14-bp ins/ins genotype (p < 0.01). Taken together, our results suggested that the HLA-G 14-bp indel polymorphism may be a marker for genetic susceptibility to HCC in Chinese populations. Further studies from different populations with larger sample size are warranted to validate our findings.

The marvelously diverse Orchidaceae constitutes the largest family of angiosperms. The genus Cymbidium in Orchidaceae is well known for its unique vegetation, floral morphology, and flower scent traits. Here, a chromosome-scale assembly of the genome of Cymbidium ensifolium (Jianlan) is presented. Comparative genomic analysis showed that C. ensifolium has experienced two whole-genome duplication (WGD) events, the most recent of which was shared by all orchids, while the older event was the τ event shared by most monocots. The results of MADS-box genes analysis provided support for establishing a unique gene model of orchid flower development regulation, and flower shape mutations in C. ensifolium were shown to be associated with the abnormal expression of MADS-box genes. The most abundant floral scent components identified included methyl jasmonate, acacia alcohol and linalool, and the genes involved in the floral scent component network of C. ensifolium were determined. Furthermore, the decreased expression of photosynthesis-antennae and photosynthesis metabolic pathway genes in leaves was shown to result in colorful striped leaves, while the increased expression of MADS-box genes in leaves led to perianth-like leaves. Our results provide fundamental insights into orchid evolution and diversification.