The dominant model of sex chromosome evolution posits that recombination is suppressed between emerging X and Y chromosomes in order to resolve sexual conflict. (nature.com)
Sex chromosomes are typically thought to evolve as recombination is halted between a homologous pair of chromosomes in one sex. (nature.com)
The sex chromosomes of the guppy ( Poecilia reticulata ) have been of interest for more than a century, following early reports that many sexually selected colour traits are passed through the patriline on the Y chromosome 8 , 9 . (nature.com)
Even though the guppy sex chromosomes are a classic model for the study of sexual conflict and sex chromosome divergence, little is actually known about the pattern of divergence between the X and Y chromosomes. (nature.com)
Also needed for efficient completion of homologous synapsis by influencing crossover distribution along the chromosomes affecting both crossovers and non-crossovers pathways. (affbiotech.com)
Our analysis illustrates the autosomal origin of the mammalian sex chromosomes, the stepwise process that led to the progressive loss of recombination between X and Y, and the extent of subsequent degradation of the Y chromosome. (inra.fr)
Sex chromosomes differ from other chromosomes in the striking divergence they often show in size, structure, and gene content. (nih.gov)
Not only do they possess genes controlling sex determination that are restricted to either the X or Y (or Z or W) chromosomes, but in many taxa they also include recombining regions. (nih.gov)
It is now clear that the evolution of the PAR differs in important ways from that of genes in either the non-recombining regions of sex chromosomes or the autosomes. (nih.gov)
Analyses of asexual lineages with a range of ages will provide an unprecedented opportunity to evaluate the genome-wide causes and consequences of the loss of recombination, and such analyses are further enhanced by the presence of two chromosomes that never recombine, even via male transmission. (grantome.com)
Loss of recombination1
Although we have a detailed understanding of the evolutionary consequences of the loss of recombination for sex chromosome evolution 1 , 2 , we still do not understand the evolutionary forces acting to halt recombination in the first place. (nature.com)
Chromosome8
These results provide empirical support for longstanding models of sex chromosome catalysis, and suggest an important role for sexual selection and sexual conflict in genome evolution. (nature.com)
The dominant theoretical model for the early stages of sex chromosome evolution 3 , 4 , 5 predicts that recombination will be selected against in the region between a sex determining gene and a nearby locus with alleles of sex-specific effect. (nature.com)
Therefore, in this system, current models of sex chromosome evolution predict that recombination would be selected against between the sex determining locus and linked loci involved in colouration. (nature.com)
Plays a key role in chromosome recombination and chromosome structure development during meiosis. (affbiotech.com)
The human X chromosome has a unique biology that was shaped by its evolution as the sex chromosome shared by males and females. (inra.fr)
LINE1 repeat elements cover one-third of the X chromosome, with a distribution that is consistent with their proposed role as way stations in the process of X-chromosome inactivation. (inra.fr)
Finally, as only about half of the genotypes to be sequenced are capable of male production, comparative analyses will provide insight into the mechanisms of sex determination in this system, clarifying the proposed existence of a nonrecombining mating-system chromosome, and evaluating the consequences of such a genetic environment on an otherwise freely recombining genetic background. (grantome.com)
The highly skewed distribution of recombination events towards the chromosome ends in zebra finches and other estrildid species may function to minimize crossovers in the inverted regions. (biomedcentral.com)
Homologous3
Divergence in one region of 18S rRNA appears to be the result of a gene conversion event, in which recombination with a homologous gene of chloroplast origin led to the complete replacement of a helix in this ribosomal RNA. (biomedcentral.com)
[ 7 , 8 ] Sister chromatid exchanges are considered a sensitive indicator for cell genome instability, as they are thought to be the outcome of DNA double-strand breaks resulting from homologous recombination repair. (medscape.com)
In heterokaryotypic individuals (those that are heterozygous for an inversion) recombination within the inverted region is largely suppressed, either because homologous pairing is partially inhibited or because crossovers give rise to unbalanced gametes (carrying deletions or duplications) which will lead to the death of the zygote [ 1 ]. (biomedcentral.com)
Heterogametic sex1
In these 'pseudoautosomal regions' (PARs), sequence homology is maintained by meiotic pairing and exchange in the heterogametic sex. (nih.gov)
Meiotic recombination3
Meiotic recombination introduces variation around that expectation (Mendelian noise) and related pedigree founders systematically bias Pedigree F downward. (nature.com)
Effects of meiotic recombination on Marker F were reversed, such that the same number of molecular markers yielded more precise estimates of GWIBD in zebra finches than in humans. (nature.com)
Required at early steps in meiotic recombination that leads to non-crossovers pathways. (affbiotech.com)
Ratios4
In theory, stocking YY males or ZZ females would allow managers to skew sex ratios until populations collapse. (geneconvenevi.org)
In the isopod Armadillidium vulgare, many females produce progenies with female-biased sex ratios, owing to two feminizing sex ratio distorters (SRD): Wolbachia endosymbionts and the f element. (geneconvenevi.org)
1995. Primary and secondary sex ratios in monogyne colonies of the fire ant Solenopsis invicta. (utexas.edu)
In multivariate analyses, women who did not discuss postpartum family planning with their husbands, had not used contraception previous to the recent birth, and had experienced physical violence or forced sex were more likely to not use postpartum contraception (adjusted odds ratios=1.47-1.77). (who.int)
Genome3
The overall sampling scheme is also designed to yield novel insights into three unsolved problems in evolutionary and population genetics: 1) the genome-wide causes and consequences of the loss of genetic recombination;2) the impact of small population size on genomic integrity;and 3) the mechanisms by which introns become established in protein-coding genes. (grantome.com)
However, while asexual and self-fertilizing individuals transmit all of their genes to their offspring, individuals that reproduce through sex transmit only half of their genome. (elifesciences.org)
High frequency intra- and intermolecular recombination among large repeated sequences is the rule, generating a heterogeneous pool of genome configurations within a single individual [ 12 - 14 ]. (biomedcentral.com)
Loci1
If the recombination frequency is less than 50% we say the two loci are linked. (goodgraeff.com)
Suppression1
First, the study species harbors a large number of permanently asexual lineages, resulting from an unusual system of sex-limited meiosis suppression that promotes the recurrent production of novel asexual clones via backcrossing of males to the sexual species. (grantome.com)
Evolutionary5
Here we review the distribution and structure of PARs among animals and plants, the theoretical predictions concerning their evolutionary dynamics, the reasons for their persistence, and the diversity and content of genes that reside within them. (nih.gov)
Collection of hundreds of neo-introns, analysis of their molecular features, and elucidation of their genealogical distributions will set the stage for future functional work on the mechanisms of intron origin, one of the great mysteries in evolutionary genomics. (grantome.com)
The existence of sex - broadly defined as the coming together of genes from different individuals - is one of the big evolutionary puzzles. (elifesciences.org)
and hence, understanding the maintenance of sex is one of the fundamental challenges in evolutionary biology. (elifesciences.org)
To counteract this two-fold cost of sex, sexual outcrossing is assumed to provide both ecological and evolutionary advantages ( Otto, 2009 ). (elifesciences.org)
20221
Nigéria, en décembre 2022 et publie depuis lors des rapports mensuels. (who.int)
Variation1
The distributions of the total number of recombination events per gamete, among the eight mothers of the CEPH families, were significantly different, and this variation was not due to maternal age. (nih.gov)
Genes2
Fine-scale recombination occurs in hotspots of varying intensity along the sequence, and is enriched near genes. (inra.fr)
Many pathogens possess the capacity for sex - here defined in its broadest sense as the coming together of genes from different individuals ( Lehtonen and Kokko, 2014 ) - despite being able to reproduce also asexually and/or via selfing. (elifesciences.org)
Linkage1
PARs are unique genomic regions, exhibiting some features of autosomes, but they are also influenced by their partial sex linkage. (nih.gov)
Alleles1
Polygenic traits have a bell-shaped distribution in a population with most individuals inheriting various combinations of alleles and falling within the middle range of the curve for a particular trait. (goodgraeff.com)
Mutation1
Because of its maternal inheritance, high mutation price and insufficient recombination mtDNA displays a definite picture of feminine human dispersion, leading to the distribution of its lineages into continent particular haplogroup. (monossabios.com)
Heterogeneous1
The heterogeneous distribution of recessive deleterious mutations, the environment and other genetic factors like epistatic interactions are introducing noise into that relation. (nature.com)
Organisms1
A female-biased sex ratio is considered advantageous for the cytoplasmic elements that inhabit sexually reproducing organisms. (geneconvenevi.org)
Differences2
Sex differences at the genetic/epigenetic level in early development. (ubc.ca)
The achieved information between quantum and elements can win a better environment of intersectional concentration maturation and distribution differences at atomistic vicinity Shop. (bob-fernsehdienst.de)
Strains2
Typically a pre-requisite of sex in pathogens is for at least two different strains to infect the same host. (elifesciences.org)
Identifying areas and populations where pathogens have sex can help to identify when and where new strains are most likely to emerge. (elifesciences.org)
Diversity1
Populations supporting high levels of coinfection -a prerequisite of sex - result in hotspots of novel genetic diversity. (elifesciences.org)
Ratio2
Stalk-eyed flies in the genus Teleopsis carry selfish genetic elements that induce sex ratio meiotic drive (SR) and impact the fitness of male and female carriers. (geneconvenevi.org)
The sex ratio (SR) X-linked meiotic drive system in stalk-eyed flies destroys Y-bearing sperm. (geneconvenevi.org)
Reproductive1
Given that sex is assumed to come at a cost, these mixed reproductive strategies typical of pathogens have remained puzzling. (elifesciences.org)
Frequency1
These traits appear with equal frequency in both sexes. (goodgraeff.com)
Possess1
Many pathogens possess the capacity for sex through outcrossing, despite being able to reproduce also asexually and/or via selfing. (elifesciences.org)
Suggests1
This suggests that gene replacement somehow occurred by recombination at the very ends of rpl36 , without the level and length of similarity normally expected to support recombination. (biomedcentral.com)
Role1
This protein plays a pivotal role in DNA recombination and repair. (medscape.com)
Sexual1
Carriage of Neisseria meningitidis in men who have sex with men presenting to public sexual health clinics, New York City. (cdc.gov)
Study1
It has been tricky to study due to the microscopic size of pathogens and the difficulties of identifying different sexes. (elifesciences.org)
Function1
Random Variables:- Notion of a Random variable, Distribution function and its properties. (careers360.com)
Impact1
et que les fruits en développement ont un impact négatif sur les dynamiques des réserves en azote et en zinc dans les branches ainsi que sur la production des fleurs femelles l'année suivante. (cnrs.fr)
Case1
Normal distribution as limiting case of Binomial and Poisson distributions. (careers360.com)