background: free fetal dna (ffd) in maternal plasma/serum has increasingly become the source of fetal material for diagnostic purposes in recent years. this source of fetal material can be used for sex determination. rh typing paternally inherited sequences and compound heterozygosity. reports on the lack of consistent pcr amplification of y-chromosome sequences of ffd in maternal plasma/serum ...

Of prime importance in evolutionary biology are the description of pattern and explanations of process. Frequently, however, multiple processes can explain a given pattern. Such cases require experimental protocols or research criteria to distinguish among alternatives so pattern can be critically assigned to process. Noteworthy examples of this approach include evaluating adaptations and ident...

Despite the prevalence of sex in animal kingdom, we have only limited understanding of how sex is determined and evolved in many taxa. The mollusc Pacific oyster Crassostrea gigas exhibits complex modes of sexual reproduction that consists of protandric dioecy, sex change, and occasional hermaphroditism. This complex system is controlled by both environmental and genetic factors through unknown...

Here we introduce a new model species, Silene colpophylla, that could facilitate research of sex chromosome evolution and sex-determining systems. This species is related to the well-established dioecious plant model Silene latifolia. Our results show that S. colpophylla is, similarly to S. latifolia, a male heterogametic species, but its sex chromosomes have evolved from a different pair of au...

Evolutionary transitions between sex-determining mechanisms (SDMs) are an enigma. Among vertebrates, individual sex (male or female) is primarily determined by either genes (genotypic sex determination, GSD) or embryonic incubation temperature (temperature-dependent sex determination, TSD), and these mechanisms have undergone repeated evolutionary transitions. Despite this evolutionary lability...

There exists extraordinary variation among species in the degree and nature of sex chromosome divergence. However, much of our knowledge about sex chromosomes is based on comparisons between deeply diverged species with different ancestral sex chromosomes, making it difficult to establish how fast and why sex chromosomes acquire variable levels of divergence. To address this problem, we studied...