Microbial Genes in the Human Genome: Lateral Transfer or Gene Loss?

Science ◽  
2001 ◽  
Vol 292 (5523) ◽  
pp. 1903-1906 ◽  
Author(s):  
S. L. Salzberg
PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10085
Author(s):  
Nagarjun Vijay

Background The genomic sequences of centromeres, as well as the set of proteins that recognize and interact with centromeres, are known to quickly diverge between lineages potentially contributing to post-zygotic reproductive isolation. However, the actual sequence of events and processes involved in the divergence of the kinetochore machinery is not known. The patterns of gene loss that occur during evolution concomitant with phenotypic changes have been used to understand the timing and order of molecular changes. Methods I screened the high-quality genomes of twenty budding yeast species for the presence of well-studied kinetochore genes. Based on the conserved gene order and complete genome assemblies, I identified gene loss events. Subsequently, I searched the intergenic regions to identify any un-annotated genes or gene remnants to obtain additional evidence of gene loss. Results My analysis identified the loss of four genes (NKP1, NKP2, CENPL/IML3 and CENPN/CHL4) of the inner kinetochore constitutive centromere-associated network (CCAN/also known as CTF19 complex in yeast) in both the Naumovozyma species for which genome assemblies are available. Surprisingly, this collective loss of four genes of the CCAN/CTF19 complex coincides with the emergence of unconventional centromeres in N. castellii and N. dairenensis. My study suggests a tentative link between the emergence of unconventional point centromeres and the turnover of kinetochore genes in budding yeast.


2004 ◽  
Vol 12 (01) ◽  
pp. 91-103
Author(s):  
FEI MA ◽  
YONGLONG ZHUANG ◽  
LIMING CHEN ◽  
LUPING LIN ◽  
YANDA LI ◽  
...  

It is becoming clear that alternative splicing plays an important role in expanding protein diversity. However, the previous studies on codons usage did not distinguish alternative splicing from non-alternative splicing. Do codon usage patterns hold distinctions between them? Thus, we attempted to systematically compare the differences of synonymous codon usage patterns between alternatively and non-alternatively spliced genes by analyzing the large datasets from human genome. The results indicated:(1) There are highly significant differences in the average Nc values between non-alternatively spliced genes and the longer isoform genes as well as the shorter isoform genes, and the level of codon usage bias of non-alternatively spliced genes is to some extent higher than that in alternatively spliced genes.(2) Very extensive heterogeneity of G+C content in silent third codon position (GC3s) was evident among these genes, and it could be also shown there are highly significant differences in the average GC3s values between non-alternatively spliced genes and the longer isoform genes as well as the shorter isoform genes.(3) The Nc-plots and correspondence analysis reveal that codon usage bias are mainly dominated by mutation bias, and no correlation between gene expression level and synonymous codon biased usage is found in human genes.(4) Overall codon usage data analysis indicated that the C-ending codons usage has a highly significant differences between the longer isoform genes and non-alternatively spliced genes as well as the shorter isoform genes, it further found out that there is no significant differences of C-ending codons usage between the shorter isoform genes and non-alternatively spliced genes.Finally, our results seem to imply that alternative splicing gene may originate from non-alternative splicing gene, and may be created by DNA mutation or gene fusion, and be retained through nature selection and adaptive evolution.


Genes ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 40 ◽  
Author(s):  
Yan He ◽  
Chengfu Yuan ◽  
Lichan Chen ◽  
Mingjuan Lei ◽  
Lucas Zellmer ◽  
...  
Keyword(s):  

2019 ◽  
Vol 63 (6) ◽  
pp. 757-771 ◽  
Author(s):  
Claire Francastel ◽  
Frédérique Magdinier

Abstract Despite the tremendous progress made in recent years in assembling the human genome, tandemly repeated DNA elements remain poorly characterized. These sequences account for the vast majority of methylated sites in the human genome and their methylated state is necessary for this repetitive DNA to function properly and to maintain genome integrity. Furthermore, recent advances highlight the emerging role of these sequences in regulating the functions of the human genome and its variability during evolution, among individuals, or in disease susceptibility. In addition, a number of inherited rare diseases are directly linked to the alteration of some of these repetitive DNA sequences, either through changes in the organization or size of the tandem repeat arrays or through mutations in genes encoding chromatin modifiers involved in the epigenetic regulation of these elements. Although largely overlooked so far in the functional annotation of the human genome, satellite elements play key roles in its architectural and topological organization. This includes functions as boundary elements delimitating functional domains or assembly of repressive nuclear compartments, with local or distal impact on gene expression. Thus, the consideration of satellite repeats organization and their associated epigenetic landmarks, including DNA methylation (DNAme), will become unavoidable in the near future to fully decipher human phenotypes and associated diseases.


1994 ◽  
Vol 39 (9) ◽  
pp. 878-879 ◽  
Author(s):  
David C. Rowe
Keyword(s):  

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