scholarly journals Novel approach to incorporate information about recessive lethal genes increases the accuracy of genomic prediction for mortality traits

Heredity ◽  
2020 ◽  
Vol 125 (3) ◽  
pp. 155-166
Author(s):  
Grum Gebreyesus ◽  
Goutam Sahana ◽  
A. Christian Sørensen ◽  
Mogens S. Lund ◽  
Guosheng Su
Keyword(s):  
Genomic Prediction ◽  
Recessive Lethal ◽  
Novel Approach ◽  
Lethal Genes

The role of the genome in the development of the haploid syndrome in Anura

Development ◽  
1966 ◽  
Vol 16 (3) ◽  
pp. 559-568
Author(s):  
Louie Hamilton
Keyword(s):  
Good Evidence ◽  
Contributory Factor ◽  
Diploid Nucleus ◽  
Haploid Nucleus ◽  
Recessive Lethal ◽  
Partial Failure ◽  
Lethal Genes

The problem of the factors involved in the development of the haploid syndrome in anuran embryos is as yet unsolved. It is known that about 90 % of all haploid frog embryos develop the haploid syndrome, which is characterized by the presence of oedema and sluggishness, by reduction in pigmentation and in the efficiency of the heart and circulation, and by a partial failure of the gut to coil and of muscle to differentiate. The two most favoured explanations of the development of the haploid syndrome have been nucleocytoplasmic imbalance, since a haploid nucleus is only half the size of a diploid nucleus in the same-sized egg, and unmasked recessive lethal genes. There is good evidence that an abnormal nucleocytoplasmic ratio is an important contributory factor in the development of the haploid syndrome. Briggs (1949) compared populations of haploids developing from large and small eggs and Subtelny (1958) compared the development of haploids and homozygous diploids which possessed a reduplicated set of haploid chromosomes.

scholarly journals Reliabilities of Genomic Prediction for Young Stock Survival Traits Using 54K SNP Chip Augmented With Additional Single-Nucleotide Polymorphisms Selected From Imputed Whole-Genome Sequencing Data

2021 ◽  
Vol 12 ◽  
Author(s):  
Grum Gebreyesus ◽  
Mogens Sandø Lund ◽  
Goutam Sahana ◽  
Guosheng Su
Keyword(s):  
Genomic Prediction ◽  
Component Model ◽  
Whole Genome ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Young Stock ◽  
Recessive Lethal ◽  
Percentage Points ◽  
Two Component ◽  
Prediction Reliability

This study investigated effects of integrating single-nucleotide polymorphisms (SNPs) selected based on previous genome-wide association studies (GWASs), from imputed whole-genome sequencing (WGS) data, in the conventional 54K chip on genomic prediction reliability of young stock survival (YSS) traits in dairy cattle. The WGS SNPs included two groups of SNP sets that were selected based on GWAS in the Danish Holstein for YSS index (YSS_SNPs, n = 98) and SNPs chosen as peaks of quantitative trait loci for the traits of Nordic total merit index in Denmark–Finland–Sweden dairy cattle populations (DFS_SNPs, n = 1,541). Additionally, the study also investigated the possibility of improving genomic prediction reliability for survival traits by modeling the SNPs within recessive lethal haplotypes (LET_SNP, n = 130) detected from the 54K chip in the Nordic Holstein. De-regressed proofs (DRPs) were obtained from 6,558 Danish Holstein bulls genotyped with either 54K chip or customized LD chip that includes SNPs in the standard LD chip and some of the selected WGS SNPs. The chip data were subsequently imputed to 54K SNP together with the selected WGS SNPs. Genomic best linear unbiased prediction (GBLUP) models were implemented to predict breeding values through either pooling the 54K and selected WGS SNPs together as one genetic component (a one-component model) or considering 54K SNPs and selected WGS SNPs as two separate genetic components (a two-component model). Across all the traits, inclusion of each of the selected WGS SNP sets led to negligible improvements in prediction accuracies (0.17 percentage points on average) compared to prediction using only 54K. Similarly, marginal improvement in prediction reliability was obtained when all the selected WGS SNPs were included (0.22 percentage points). No further improvement in prediction reliability was observed when considering random regression on genotype code of recessive lethal alleles in the model including both groups of the WGS SNPs. Additionally, there was no difference in prediction reliability from integrating the selected WGS SNP sets through the two-component model compared to the one-component GBLUP.

Biosystematic studies in the Stylidium crassifolium species complex (Stylidiaceae)

1979 ◽  
Vol 27 (1) ◽  
pp. 27 ◽  
Author(s):  
BJ Banyard ◽  
SH James
Keyword(s):  
Species Complex ◽  
Genetic System ◽  
Lethal Gene ◽  
Great Efficiency ◽  
Intermediate Species ◽  
Gene Arrays ◽  
Recessive Lethal ◽  
Tetraploid Form ◽  
Diploid Populations ◽  
Lethal Genes

Stylidium elongatum Benth. (n = 13, 26) and Stylidium crassifolium R. Br. (n = 14, 28) have been restored to specific status and a morphologically intermediate species, Stylidium confluens sp. nov. (n = 14), is described. Polyploid entities in the complex have not been given taxonomic ranks although the tetraploid form of elongatum may be considered worthy of subspecific rank, as it is ecologically distinct and contiguously allopatric to its progenitor and to confluens, forming a buffer between these two diploid entities. Tetraploid populations in crassifolium occur within the distributional range of the diploid. All three species carry recessive lethal gene arrays which eliminate the products of self-pollination with great efficiency and result in crosses between close populations yielding seed more effectively than crosses within populations. There is evidence that interpopulational coadaptation may break down with increasing distance between populations. Polyploidy in crassifolium is probably a conservative response in the genetic system of a species where concentrations of lethal genes in small diploid populations became disadvantageous.

scholarly journals Colonization of the Americas by Drosophila subobscura: lethal-gene allelism and association with chromosomal arrangements.

Genetics ◽  
1995 ◽  
Vol 140 (4) ◽  
pp. 1297-1305
Author(s):  
F Mestres ◽  
L Serra ◽  
F J Ayala
Keyword(s):  
Drosophila Subobscura ◽  
Rapid Expansion ◽  
Lethal Gene ◽  
Latitudinal Cline ◽  
Recessive Lethal ◽  
Central California ◽  
High Incidence ◽  
Palearctic Species ◽  
Lethal Allelism ◽  
Lethal Genes

Abstract Drosophila subobscura is a Palearctic species that has recently colonized the Americas. It was first found in 1978 in Puerto Montt, Chile, and in 1982 in Port Townsend, WA. The colonization and rapid expansion of the species in western South and North America provides distinctive opportunities for investigating the process of evolution in action. The inversion polymorphism in the O chromosome from populations of central California and northern Washington, separated by 1300 km, corresponds to a previously observed latitudinal cline, also observed in Europe. Recessive lethal genes are not randomly distributed among the chromosomal arrangements. The incidence of lethal allelism is high, yielding unrealistically low estimates of the effective size of these populations (on the order of 1000 individuals). The high incidence of lethal allelism is likely to be a consequence of the low number of the American colonizers (on the order of 10-100 individuals), but the persistence of the allelism over several years suggests that some lethal-carrying chromosomes may be heterotic owing to shared associations between lethal and other genes.

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