The association of 22 Y chromosome short tandem repeat loci with initiative-aggressive behavior

The association of 20 short tandem repeat loci of autosomal chromosome with male schizophrenia

INTRODUCTION

Schizophrenia's heritability and familial transmission have been known for several decades. The male-specific Y chromosome plays an important role in schizophrenia. Short tandem repeats (STRs)have been recognized as risk genes in the development of schizophrenia. Here, we investigated the association between male schizophrenia and Y-chromosomal STRs loci.

METHODS

We recruited 355 patients with schizophrenia and 473 healthy males for physical examination and amplified them with a PowerPlex 21 System fluorescence-labeled composite amplification System. Then, the resultant products were separated by electrophoresis and further detected. Finally, differences in allele and genotype frequency distributions of STR loci were observed.

RESULTS

Our results showed that all 20 STR loci were in accordance with Hardy-Weinberg's law (p > .05). There were statistically significant differences in alleles of D13S317 and D5S818 loci and genotype frequency distribution between the two groups (alleles: p = .039, p = .022, respectively; genotype: p = .0004, p = .011, respectively). However, there was no difference in the other autosomal 18 STR loci between the two groups (p > .05). Univariate analysis showed that the frequency distribution differences of allele 11 and genotype 10-11 at the D13S317 locus between the two groups were significant (compared to the controls, p = 0.005, odds ratio (OR) = 1.37, 95%b confidence interval (CI) = 1.10-1.71, compared to the controls, p = .0000002, OR = 3.92, 95% CI = 2.27-6.77, respectively). The frequency distribution differences of allele 7 and genotype 7-10 at D5S818 between the two groups were significant (compared to the controls, p = .0006, OR = 3.42, 95% CI = 1.63-7.16, compared to the controls, p = .0011, OR = 8.24, 95% CI = 1.83-37.05, respectively).

CONCLUSION

Polymorphisms of the D13S317 and D5S818 loci may be predisposing factors for schizophrenia.

Geographical contrasts of Y-chromosomal haplogroups from wild and domestic goats reveal ancient migrations and recent introgressions

By their paternal transmission, Y-chromosomal haplotypes are sensitive markers of population history and male-mediated introgression. Previous studies identified biallelic single-nucleotide variants in the SRY, ZFY, DDX3Y genes, which in domestic goats identified four major Y-chromosomal haplotypes Y1A, Y1B, Y2A and Y2B with a marked geographic partitioning. Here, we extracted goat Y-chromosomal variants from whole-genome sequences of 386 domestic goats (75 breeds) and 7 wild goat species, which were generated by the VarGoats goat genome project. Phylogenetic analyses indicated domestic haplogroups corresponding to Y1B, Y2A and Y2B, respectively, whereas Y1A is split into Y1AA and Y1AB. All five haplogroups were detected in 26 ancient DNA samples from southeast Europe or Asia. Haplotypes from present-day bezoars are not shared with domestic goats and are attached to deep nodes of the trees and networks. Haplogroup distributions for 186 domestic breeds indicate ancient paternal population bottlenecks and expansions during the migrations into northern Europe, eastern and southern Asia and Africa south of the Sahara. In addition, sharing of haplogroups indicates male-mediated introgressions, most notably an early gene flow from Asian goats into Madagascar and the crossbreeding that in the 19^th century resulted in the popular Boer and Anglo-Nubian breeds. More recent introgressions are those from European goats into the native Korean goat population and from Boer goat into Uganda, Kenya, Tanzania, Malawi and Zimbabwe. This study illustrates the power of the Y-chromosomal variants for reconstructing the history of domestic species with a wide geographic range.

Forensic Value of Genetic Variants Associated with Anti-Social Behavior

Insanity defense is sometimes invoked in criminal cases, and its demonstration is usually based on a multifactorial contribution of behavioural, clinical, and neurological elements. Neuroradiological evidence of structural alterations in cerebral areas that involve decision-making and moral reasoning is often accepted as a useful tool in these evaluations. On the other hand, the genetic predisposition to anti-social behavior is still controversial. In this paper, we describe two cases of violent crimes committed by young carriers of genetic variants associated with personality disorder; both the defendants claimed to be insane at the time of the crime. We discuss these cases and review the scientific literature regarding the relationship between legal incapacity/predisposition to criminal behavior and genetic mutations. In conclusion, despite some genetic variants being able to influence several cognitive processes (like moral judgement and impulse control), there is currently no evidence that carriers of these mutations are, per se, incapable of intentionally committing crimes.

Cold-Blooded and on Purpose: A Review of the Biology of Proactive Aggression

Proactive aggression (PA) is a planned and unprovoked form of aggression that is most often enacted for personal gain or in anticipation of a reward. Frequently described as "cold-blooded" or goal oriented, PA is thought to be associated with low autonomic arousal. With this view in mind, we performed a scoping review of the biological correlates of PA and identified 74 relevant articles. Physiological findings indicated a robust association between PA and reduced resting heart rate, and to a lesser extent a relationship between PA and decreased heart rate and skin conductance reactivity, perhaps indicating dampened sympathetic function. The twin literature identified PA as a heritable trait, but little evidence implicates specific genes in the pathogenesis of PA. Neuroimaging studies of PA pinpoint impaired amygdala function in the assessment and conditioning of aversive stimuli, which may influence the establishment of behavioral patterns. Nodes of the default mode network were identified as possible neural correlates of PA, suggesting that altered function of this network may be involved in the genesis of PA. Given the overlap of PA with reactive aggression and the overall behavioral complexity of PA, it is clear that multiple endophenotypes of PA exist. This comprehensive review surveys the most salient neurobiologically informed research on PA.

Mosaic trisomy 20 and mitigation in capital crimes sentencing: A review and case report

Trisomy 20 is a genetic abnormality in which individuals have an extra copy of chromosome 20. Complete trisomy 20 is rare and believed to be incompatible with life. A mosaic form of trisomy 20, in which only some cells or tissues contain the extra chromosome, is a relatively commonly encountered chromosomal abnormality found during prenatal testing, and c. 90% result in a normal phenotype. However, despite the absence of a consistent phenotype, certain findings have been reported across multiple cases of mosaic trisomy 20. These include an array of morphological findings, developmental delays, and learning disabilities. Beyond physical manifestations, a wide range of developmental and learning delays have also been reported. In this work, we provide an overview of the trisomy 20 literature and a case report of a young adult male with mosaic trisomy 20 who committed homicide. His developmental and life history, eventual diagnosis of mosaic trisomy 20, similarities and differences in his condition compared with prior research findings, and potentially new phenotypic findings associated with trisomy 20 that he manifested (childhood visual hallucinations, self-injury, polydactyly) are presented. Additionally, the potential role of this genetic diagnosis in his neuropsychiatric history and its successful application as a mitigating factor at his capital sentencing trial are described. We did not identify other similar cases during our search of major scientific and legal databases. As a backdrop, the use of genetics in criminal trials is on the rise, and courts are increasingly likely to accept behavioral genetics evidence; therefore, it is crucial that the legal system is well acquainted with the opportunities and limitations of these approaches.