Discordant associations of educational attainment with ASD and ADHD implicate a polygenic form of pleiotropy

Autism Spectrum Disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD) are complex co-occurring neurodevelopmental conditions. Their genetic architectures reveal striking similarities but also differences, including strong, discordant polygenic associations with educational attainment (EA). To study genetic mechanisms that present as ASD-related positive and ADHD-related negative genetic correlations with EA, we carry out multivariable regression analyses using genome-wide summary statistics (N = 10,610–766,345). Our results show that EA-related genetic variation is shared across ASD and ADHD architectures, involving identical marker alleles. However, the polygenic association profile with EA, across shared marker alleles, is discordant for ASD versus ADHD risk, indicating independent effects. At the single-variant level, our results suggest either biological pleiotropy or co-localisation of different risk variants, implicating MIR19A/19B microRNA mechanisms. At the polygenic level, they point to a polygenic form of pleiotropy that contributes to the detectable genome-wide correlation between ASD and ADHD and is consistent with effect cancellation across EA-related regions.

Evidence for hexasomic inheritance in Chrysanthemum morifolium Ramat. based on analysis of EST-SSR markers

Chrysanthemums (Chrysanthemum morifolium Ramat.) are ornamental flowers, which are famous worldwide. The mode of inheritance has great implications for the genetic analysis of polyploid species. However, genetic analysis of chrysanthemum has been hampered because of its controversial inheritance mode (disomic or hexasomic). To classify the inheritance mode of chrysanthemums, an analysis of three approaches was carried out in an F1 progeny of 192 offspring using 223 expressed sequence tag-simple sequence repeat (EST-SSR) markers. The analysis included segregation analysis, the ratio of simplex marker alleles linked in coupling to repulsion, as well as the transmission and segregation patterns of EST-SSR marker alleles. After segregation analysis, 204 marker alleles fit hexasomic inheritance and 150 marker alleles fit disomic inheritance, showing that marker alleles were inherited predominantly in a hexasomic manner. Furthermore, the results of the analysis of allele configuration and segregation behavior of five EST-SSR markers also suggested random pairing of chromosomes. Additionally, the ratio of simplex marker alleles linked in coupling to repulsion was 1:0, further supporting hexasomic inheritance. Therefore, it could be inferred that chrysanthemum is a complete or near-complete hexasome.

QTL Mapping for Domestication-Related Characteristics in Field Cress (Lepidium campestre)—A Novel Oil Crop for the Subarctic Region

Domestication of a new crop requires identification and improvement of desirable characteristics Field cress (Lepidium campestre) is being domesticated as a new oilseed crop, particularly for northern temperate regions.. In the present study, an F2 mapping population and its F3 progenies were used to identify quantitative trait loci (QTLs) for plant height (PH), number of stems per plant (NS), stem growth orientation (SO), flowering habit (FH), earliness (ER), seed yield per plant (SY), pod shattering resistance (SHR), and perenniality (PE). A highly significant correlation (p < 0.001) was observed between several pairs of characteristics, including SY and ER (negative) or ER and PE (positive). The inclusive composite interval mapping approach was used for QTL mapping using 2330 single nucleotide polymorphism (SNP) markers mapped across the eight field cress linkage groups. Nine QTLs were identified with NS, PH, SO, and PE having 3, 3, 2, and 1 QTLs, explaining 21.3%, 29.5%, 3.8%, and 7.2% of the phenotypic variation, respectively. Candidate genes behind three of the QTLs and favorable marker alleles for different classes of each characteristic were identified. Following their validation through further study, the identified QTLs and associated favorable marker alleles can be used in marker-aided breeding to speed up the domestication of field cress.

Polymorphism genes CSN3, PIT-1, PRL, GH in Yaroslavskaya breed of cows in association with the indicators of milk productivity

A common component of all breeding programs for working with breeds, populations, and herds is to increase the genetic potential, preserve and improve the gene pool of valuable domestic breeds of farm animals, including dairy cattle. Methods of molecular genetics allow us to study, evaluate, and predict breeding, productive traits that persistently transmit and progressively develop in generations. The purpose of these researches was to study the polymorphism of genes: Kappacasein – CSN3, pituitary transcription factor – PIT-1, prolactin – PRL, somatotropin – GH and searching the association of their polymorphic variants with the indicators of dairy productivity of Yaroslavlskaya breed of cows bred in the Stavropol Territory. It has been found by using PCR-PDRF methods that the polymorphism of the studied genes is represented by two alleles: gene CSN3 – alleles CSN3A and CSN3B ; gene PIT-1 – PIT-1A and PIT-1B ; gene PRL – PRLA and PRLB , gene GH – GHL and GHV , and three genotypes – CSN3AA, CSN3BB, CSN3AB; PIT-1AA, PIT-1BB, PIT-1AB; PRLAA, PRLBB, PRLAB; GHLL, GHVV, GHVL, respectively. The frequency of occurrence of selectively signifi cant alleles has been determined, and genotypes of carriers of genetic markers have been identifi ed. It has been found that the specifi c weight of animals carrying genocomplexes of 4 genes and 8 desirable alleles was 0,63, of 4 genes and 7 marker alleles – 3,16, of 4 genes and 6, 5, 4 marker alleles – 20,87 %. Most of the animals (62,7 %) were carriers of genocomplexes of 4, 3, 2 genes and 2 marker alleles. The conclusion has been made about necessity of wide use of genotypes the carriers of genetic markers in the selection process that will ensure gathering in herds of Yaroslavskaya breed of desirable alleles and create conditions for improving the effi ciency of its breeding in the Stavropol Territory.

Immunogenetic analysis of brown Schwyz cattle lines

Animals of brown Schwyz breed from pedigree farms of the Smolensk region were differentiated by their belonging to lines and related groups. Identification by blood groups was carried out according to the generally accepted technique, and the genetic structure of the uterine population of each line was established using marker alleles of the EAB locus; 12 genealogical lines were identified. The number of alleles in individual lines ranged from 15 to 53, which indicates the necessary hereditary diversity for improving the breed. At the same time, the most common B2O3Y2A`2E`2G`P`Q`Y`, I1Y2E`2G`I`G``1, G3O1T1Y2E`3F`2G``, G1O` and b markers somewhat offset the differences between them. The coefficient of genetic similarity r between lines and related groups of animals ranges from 0.20 to 0.90. Interlinear differences in milk production of cows were established.

Association of LEI0258 Marker Alleles and Susceptibility to Virulent Newcastle Disease Virus Infection in Kuroiler, Sasso, and Local Tanzanian Chicken Embryos

Newcastle disease (ND) control by vaccination and an institution of biosecurity measures is less feasible in backyard chicken in developing countries. Therefore, an alternative disease control strategy like the genetic selection of less susceptible chicken genotypes is a promising option. In the present study, genetic polymorphism of LEIO258 marker and association with susceptibility to virulent Newcastle disease virus (NDV) infection in Kuroilers, Sasso, and local Tanzanian chicken embryos were investigated. Samples from high (15%) and less (15%) susceptible cohorts were genotyped by sequencing of LEI0258 marker. A total of 75 DNA sequences comprised of 29 Kuroiler, 29 local Tanzanian chickens, and 17 Sasso were analyzed. Neighbor-joining phylogenetic trees were constructed to depict the clustering of LEI0258 marker alleles and relationship with susceptibility. Alleles with frequency ≥3 were considered for association with susceptibility by the use of the inference technique. The present findings suggest that some LEI0258 marker genetic polymorphisms apart from LEI0258 marker allelic based on sizes may be linked with chicken MHC-B haplotypes that confer chickens variability in resistance or susceptibility to infections. Furthermore, these results demonstrate the presence of relationship between LEI0258 marker polymorphisms and variations in chicken susceptibility to NDV infection, which could be utilized in breeding programs designed to improve chicken disease resistance.

Introgression of allelic diversity from genetically distinct variants of Brassica rapa into Brassica napus canola and inheritance of the B. rapa alleles

Broadening of genetic diversity in spring oilseed Brassica napus L. (AACC, 2n = 38) canola is important for continued improvement of this crop. For this, the vast allelic diversity of the A genome of Brassica rapa L. (AA, 2n = 20) can be utilised. We investigated the prospect of developing canola-quality euploid B. napus lines carrying the alleles of B. rapa from F2 and BC1 (F1 × B. napus) populations of three B. napus × B. rapa interspecific crosses involving one B. napus and three genetically distinct B. rapa parents. In meiosis, the F1 AAC hybrid was expected to show normal segregation for the A genome chromosomes, whereas a range of C chromosomes from zero to nine was expected to be included in the gametes due to random segregation of this haploid set of chromosomes. Subsequent self-pollination, theoretically, should have eliminated the unpaired C chromosomes and resulted in a majority of B. rapa type. However, no B. rapa-type progeny were detected, and all progeny in the F8 conformed to be B. napus type. Correlation between parent and offspring generation, grown in greenhouse or field, was weak to moderate for seed glucosinolate content; however, the simpler genetic control of this trait, involving only the A genome loci, allowed the development of low-glucosinolate lines from this interspecific cross. Of the theoretical number of simple sequence repeat (SSR) marker alleles of B. rapa expected to be present in F4 and F8 populations, about 45% were detected in these populations, suggesting that the loss of these marker alleles occurred prior to the F4 generation. Loss of several SSR loci was also detected in these populations, which probably resulted from homoeologous pairing and rearrangements of the chromosomes of the A and C genomes. Genetic diversity analysis performed on the F8 progeny of two crosses showed that the two populations clustered into distinct groups, which demonstrates that they inherited SSR B. rapa alleles unique to each B. rapa parent. We conclude that B. rapa alleles from diverse sources can be readily incorporated into B. napus progeny by this interspecific crossing method.