scholarly journals Genetic conflict, genomic imprinting and establishment of the epigenotype in relation to growth

Reproduction ◽  
2001 ◽  
pp. 185-193 ◽  
Author(s):  
T Moore

Genomic imprinting is the process that differentially modifies the parental alleles at certain genetic loci in the parental germlines. Such modifications of DNA and chromatin are somatically heritable and cause unequal expression of the parental alleles during subsequent development. In mammals, imprinted genes encode a relatively small number of functionally heterogeneous proteins. Nevertheless, imprinted genes exert important effects, primarily on fetal development, and their deregulation is implicated in a variety of pathologies including sporadic, inherited and induced growth disorders. Imprinted loci show several unusual structural and functional characteristics that may be related to mechanistic aspects of mono-allelic expression or to modes of evolution of imprinted genetic loci. Typically, imprinted genes are clustered in certain genomic regions and have relatively reduced intronic DNA content relative to non-imprinted genes. In addition, their regulatory regions frequently contain a combination of features including tandem repeats associated with differentially methylated CpG islands and overlapping transcription of coding or non-coding RNAs. The evolution of imprinting can be understood as the stable outcome of sexual selection acting differently on the parental alleles of genes that influence parental investment in offspring. Consistent with this explanation, imprinted genes are expressed predominantly during embryonic and postnatal development in mammals and in the developing endosperm of plants, and maternal or paternal expression at imprinted loci is associated with reduced or increased parental investment, respectively. Such selective forces have implications for understanding mechanistic aspects of genome reprogramming in the early mammalian embryo.

2009 ◽  
Vol 2009 ◽  
pp. 1-7 ◽  
Author(s):  
Elias Daura-Oller ◽  
Maria Cabré ◽  
Miguel A. Montero ◽  
José L. Paternáin ◽  
Antoni Romeu

In the present study, a positive training set of 30 known human imprinted gene coding regions are compared with a set of 72 randomly sampled human nonimprinted gene coding regions (negative training set) to identify genomic features common to human imprinted genes. The most important feature of the present work is its ability to use multivariate analysis to look at variation, at coding region DNA level, among imprinted and non-imprinted genes. There is a force affecting genomic parameters that appears through the use of the appropriate multivariate methods (principle components analysis (PCA) and quadratic discriminant analysis (QDA) to analyse quantitative genomic data. We show that variables, such as CG content, [bp]% CpG islands, [bp]% Large Tandem Repeats, and [bp]% Simple Repeats, are able to distinguish coding regions of human imprinted genes.


2006 ◽  
Vol 361 (1476) ◽  
pp. 2229-2237 ◽  
Author(s):  
Anthony R Isles ◽  
William Davies ◽  
Lawrence S Wilkinson

Genomic imprinting refers to the parent-of-origin-specific epigenetic marking of a number of genes. This epigenetic mark leads to a bias in expression between maternally and paternally inherited imprinted genes, that in some cases results in monoallelic expression from one parental allele. Genomic imprinting is often thought to have evolved as a consequence of the intragenomic conflict between the parental alleles that occurs whenever there is an asymmetry of relatedness. The two main examples of asymmetry of relatedness are when there is partiality of parental investment in offspring (as is the case for placental mammals, where there is also the possibility of extended postnatal care by one parent), and in social groups where there is a sex-biased dispersal. From this evolutionary starting point, it is predicted that, at the behavioural level, imprinted genes will influence what can broadly be termed bonding and social behaviour. We examine the animal and human literature for examples of imprinted genes mediating these behaviours, and divide them into two general classes. Firstly, mother–offspring interactions (suckling, attachment and maternal behaviours) that are predicted to occur when partiality in parental investment in early postnatal offspring occurs; and secondly, adult social interactions, when there is an asymmetry of relatedness in social groups. Finally, we return to the evolutionary theory and examine whether there is a pattern of behavioural functions mediated by imprinted genes emerging from the limited data, and also whether any tangible predictions can be made with regards to the direction of action of genes of maternal or paternal origin.


Genomics ◽  
2006 ◽  
Vol 88 (3) ◽  
pp. 323-332 ◽  
Author(s):  
Barbara Hutter ◽  
Volkhard Helms ◽  
Martina Paulsen

Genetics ◽  
1996 ◽  
Vol 144 (3) ◽  
pp. 1283-1295 ◽  
Author(s):  
Atsushi Mochizuki ◽  
Yasuhiko Takeda ◽  
Yoh Iwasa

Abstract In some mammalian genes, the paternally and maternally derived alleles are expressed differently: this phenomenon is called genomic imprinting. Here we study the evolution of imprinting using multivariate quantitative genetic models to examine the feasibility of the genetic conflict hypothesis. This hypothesis explains the observed imprinting patterns as an evolutionary outcome of the conflict between the paternal and maternal alleles. We consider the expression of a zygotic gene, which codes for an embryonic growth factor affecting the amount of maternal resources obtained through the placenta. We assume that the gene produces the growth factor in two different amounts depending on its parental origin. We show that genomic imprinting evolves easily if females have some probability of multiple partners. This is in conflict with the observation that not all genes controlling placental development are imprinted and that imprinting in some genes is not conserved between mice and humans. We show however that deleterious mutations in the coding region of the gene create selection against imprinting.


Reproduction ◽  
2010 ◽  
Vol 140 (3) ◽  
pp. 411-423 ◽  
Author(s):  
Philippe Arnaud

The cis-acting regulatory sequences of imprinted gene loci, called imprinting control regions (ICRs), acquire specific imprint marks in germ cells, including DNA methylation. These epigenetic imprints ensure that imprinted genes are expressed exclusively from either the paternal or the maternal allele in offspring. The last few years have witnessed a rapid increase in studies on how and when ICRs become marked by and subsequently maintain such epigenetic modifications. These novel findings are summarised in this review, which focuses on the germline acquisition of DNA methylation imprints and particularly on the combined role of primary sequence specificity, chromatin configuration, non-histone proteins and transcriptional events.


2007 ◽  
Vol 28 (1) ◽  
pp. 386-396 ◽  
Author(s):  
Trevelyan R. Menheniott ◽  
Kathryn Woodfine ◽  
Reiner Schulz ◽  
Andrew J. Wood ◽  
David Monk ◽  
...  

ABSTRACT By combining a tissue-specific microarray screen with mouse uniparental duplications, we have identified a novel imprinted gene, Dopa decarboxylase (Ddc), on chromosome 11. Ddc_exon1a is a 2-kb transcript variant that initiates from an alternative first exon in intron 1 of the canonical Ddc transcript and is paternally expressed in trabecular cardiomyocytes of the embryonic and neonatal heart. Ddc displays tight conserved linkage with the maternally expressed and methylated Grb10 gene, suggesting that these reciprocally imprinted genes may be coordinately regulated. In Dnmt3L mutant embryos that lack maternal germ line methylation imprints, we show that Ddc is overexpressed and Grb10 is silenced. Their imprinting is therefore dependent on maternal germ line methylation, but the mechanism at Ddc does not appear to involve differential methylation of the Ddc_exon1a promoter region and may instead be provided by the oocyte mark at Grb10. Our analysis of Ddc redefines the imprinted Grb10 domain on mouse proximal chromosome 11 and identifies Ddc_exon1a as the first example of a heart-specific imprinted gene.


2004 ◽  
Vol 69 (0) ◽  
pp. 465-476 ◽  
Author(s):  
C. SPILLANE ◽  
C. BAROUX ◽  
J.-M. ESCOBAR-RESTREPO ◽  
D.R. PAGE ◽  
S. LAOUEILLE ◽  
...  

2004 ◽  
Vol 69 (0) ◽  
pp. 371-380 ◽  
Author(s):  
R. MARTIENSSEN ◽  
Z. LIPPMAN ◽  
B. MAY ◽  
M. RONEMUS ◽  
M. VAUGHN

2004 ◽  
Vol 3 (3) ◽  
pp. 8-17
Author(s):  
S. A. Nazarenko

Genomic imprinting is a form of non-Mendelian epigenetic inheritance that is defined by differential gene expression depending on its parental origin — maternal or paternal. It is known about 60 imprinted genes many of which effect significantly on the fetus growth and development. Methylation of DNA cytosine bases that defines the interaction of DNA and proteins identifying the modified bases and controls the gene expression through chromatin compacting-decompacting mechanism, is a main epigenetic genom modifier. Disturbances in monoallelic gene expression lead to the development of a special class of human hereditary diseases — genomic imprinting diseases.


Author(s):  
Laura C. Kusinski ◽  
Wendy N. Cooper ◽  
Ionel Sandovici ◽  
Miguel Constância

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