A selfish genetic element confers non-mendelian inheritance in rice

image

A selfish genetic element confers non-Mendelian inheritance in rice Selfish genetic elements are pervasive in eukaryote genomes, but their role remains controversial.

Full
Answer


What is an example of a selfish gene?

Examples include cytoplasmic male sterility (see Selfish mitochondria). While mitochondrial and chloroplast genes are generally maternally inherited, B chromosomes can be preferentially transmitted through both males and females.


What are examples of Non-Mendelian inheritance?

Non-Mendelian inheritance includes extranuclear inheritance, gene conversion, infectious heredity, genomic imprinting, mosaicism, and trinucleotide repeat disorders.


Which are non-Mendelian traits of inheritance?

The following traits are considered non-Mendelian in humans:Blood type.Baldness.Hemophilia.Weight.Hair color.Eye color.Height.


What are the 3 types of non-Mendelian pattern of inheritance?

LessonComplex patterns of inheritance other than those studied by Mendel.The types of Non-Mendelian inheritance: codominance, incomplete dominance, multiple alleles, and polygenic traits.How environment affects the phenotype of an individual.


Is an example of non-Mendelian inheritance is incomplete dominance?

Incomplete dominance occurs when the phenotype of the offspring is somewhere in between the phenotypes of both parents; a completely dominant allele does not occur. For example, when red snapdragons (CRCR) are crossed with white snapdragons (CWCW), the F1hybrids are all pink heterozygotes for flower color (CRCW).


What is an example of Mendelian inheritance?

Examples of human autosomal Mendelian traits include albinism and Huntington’s disease. Examples of human X-linked traits include red-green colour blindness and hemophilia.


How do you do non-Mendelian genetics?

3:345:33Non-Mendelian Genetics – YouTubeYouTubeStart of suggested clipEnd of suggested clipSo set it up as you normally would remember you put the trait as a superscript and the Y will notMoreSo set it up as you normally would remember you put the trait as a superscript and the Y will not carry the trait because it only exists on the X chromosomes. Then fill out the punnett square.


Which of the following is a non-Mendelian law of inheritance wherein neither allele is dominant over the other?

In codominance, neither allele is dominant over the other, so both will be expressed equally in the heterozygote.


Sterility in rice via toxin and antidote

Crossing wild and domestic rice often results in hybrid sterility. Such genetic barriers can prevent the movement of potentially beneficial genes from wild rice into domestic varieties. To understand the barriers preventing gene flow, Yu et al. mapped a quantitative trait locus (QTL) that determines sterility between wild-type and domestic rice.


Abstract

Selfish genetic elements are pervasive in eukaryote genomes, but their role remains controversial. We show that qHMS7, a major quantitative genetic locus for hybrid male sterility between wild rice ( Oryza meridionalis) and Asian cultivated rice ( O. sativa ), contains two tightly linked genes [ Open Reading Frame 2 ( ORF2) and ORF3 ].


Acknowledgments

We thank Q. Yang and L. Han for providing rice germplasm and K. Olsen for discussion. Funding: Supported by National Key Research and Development Program of China (2016YFD0100301), National Natural Science Foundation of China (U1502265), and the Agricultural Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences.


What are selfish genes?

Selfish genetic elements are pervasive in eukaryote genomes, but their role remains controversial. We show that qHMS7, a major quantitative genetic locus for hybrid male sterility between wild rice (Oryza meridionalis) and Asian cultivated rice (O. sativa), contains two tightly linked genes [Open Reading Frame 2 (ORF2) and ORF3]. ORF2 encodes a toxic genetic element that aborts pollen in a sporophytic manner, whereas ORF3 encodes an antidote that protects pollen in a gametophytic manner. Pollens lacking ORF3 are selectively eliminated, leading to segregation distortion in the progeny. Analysis of the genetic sequence suggests that ORF3 arose first, followed by gradual functionalization of ORF2. Furthermore, this toxin-antidote system may have promoted the differentiation and/or maintained the genome stability of wild and cultivated rice.


What is a meiotic driver?

Meiotic drivers are parasitic loci that force their own transmission into greater than half of the offspring of a heterozygote. Many drivers have been identified, but their molecular mechanisms are largely unknown. The wtf4 gene is a meiotic driver in Schizosaccharomyces pombe that uses a poison-antidote mechanism to selectively kill meiotic products (spores) that do not inherit wtf4. Here, we show that the Wtf4 proteins can function outside of gametogenesis and in a distantly related species, Saccharomyces cerevisiae. The Wtf4poison protein forms dispersed, toxic aggregates. The Wtf4antidote can co-assemble with the Wtf4poison and promote its trafficking to vacuoles. We show that neutralization of the Wtf4poison requires both co-assembly with the Wtf4antidote and aggregate trafficking, as mutations that disrupt either of these processes result in cell death in the presence of the Wtf4 proteins. This work reveals that wtf parasites can exploit protein aggregate management pathways to selectively destroy spores.


What is TRD rice?

Transmission ratio distortion (TRD) refers to a widespread phenomenon in which one allele is transmitted by heterozygotes more frequently to the progeny than the opposite allele. TRD is considered as a mark suggesting the presence of a reproductive barrier. However, the genetic and molecular mechanisms underlying TRD in rice remain largely unknown. In the present study, a population of backcross inbred lines (BILs) derived from the cross of a japonica cultivar Nipponbare (NIP) and an indica variety 9311 was utilized to study the genetic base of TRD. A total of 18 genomic regions were identified for TRD in the BILs. Among them, 12 and 6 regions showed indica (9311) and japonica (NIP) alleles with preferential transmission, respectively. A series of F2 populations were used to confirm the TRD effects, including six genomic regions that were confirmed by chromosome segment substitution line (CSSL)-derived F2 populations from intersubspecific allelic combinations. However, none of the regions was confirmed by the CSSL-derived populations from intrasubspecific allelic combination. Furthermore, significant epistatic interaction was found between TRD1.3 and TRD8.1 suggesting that TRD could positively contribute to breaking intersubspecific reproductive barriers. Our results have laid the foundation for identifying the TRD genes and provide an effective strategy to breakdown TRD for breeding wide-compatible lines, which will be further utilized in the intersubspecific hybrid breeding programs.


Abstract

To investigate plant hybrid sterility, we studied interspecific hybrids of two cultivated rice species, Asian rice ( Oryza sativa) and African rice ( O. glaberrima ). Male gametes of these hybrids display complete sterility owing to a dozen of hybrid sterility loci, termed HS loci, but this complicated genetic system remains poorly understood.


Background

Methods that maintain immature microspores as living cells can rescue pollen aborted between meiosis and fertilization and enable genetic studies of gametophytic characteristics. Anther culture (AC) is a technique in which plants are regenerated from microspores via callus formation in in vitro culture [ 1, 2 ].


Methods

For the first experiment, we produced interspecific F 1 hybrids by crossing O. sativa L. ssp. japonica with O. glaberrima Steud.. The donor parents, O. glaberrima accessions, Acc. IRGC 104038 from Senegal (designated as WK21) and Acc.


Results

We obtained microspore-derived calli from interspecific F 1 hybrids whose male gametes were completely sterile because of the lethal effect of multiple HS loci. A total of 104 calli were obtained from 40,092 anthers of WK/Ns plants plated on CIM (Additional file 2: Table S3).


Discussion

In this study, we found that HS loci responsible for TRD of male gametophytes can act as segregation distorters in AC-induced calli (Table 1 ). This gametophytic effect was observed to directly influence the frequency of genotypes in AC-induced calli arising from HS -locus heterozygotes.


Conclusions

Taken together, our results demonstrate that the genotype segregation patterns of HS loci in AC-induced calli associated with microspore developmental stages are informative for understanding when HS loci determine the viability of male gametes.


Author information

Laboratory of Plant Breeding, Research Faculty of Agriculture, Hokkaido University, Sapporo, 060-8589, Japan

image

Leave a Comment