Evolutionary Biology of Parasitism
Eric S. Loker, Bruce V. Hofkin in Parasitology, 2015
One of several hypotheses proposed to solve this mystery relates to the Red Queen hypothesis discussed earlier; the pressure imposed by fast evolving parasites results in selection on hosts to adopt sexual reproduction. Recombination of genetic material resulting from sexual reproduction is expected to produce more diverse progeny, some of which can withstand the onslaughts of parasites. If asexual reproduction were the only possibility, then hosts would be relatively defenseless to ensure their progeny would not be attacked by parasites of the same constitution as attacked them. This supposition might be called the parasite hypothesis or Red Queen hypothesis as it relates specifically to the evolution of sex.
Evolutionary Biology of Parasitism
Eric S. Loker, Bruce V. Hofkin in Parasitology, 2023
One of several hypotheses proposed to solve this mystery relates to the Red Queen hypothesis discussed earlier; the pressure imposed by fast-evolving parasites results in selection on hosts to adopt sexual reproduction. Recombination of genetic material resulting from sexual reproduction is expected to produce more diverse progeny, some of which can withstand the onslaughts of parasites. If asexual reproduction were the only possibility, then hosts would be relatively defenseless to ensure their progeny would not be attacked by parasites of the same constitution as attacked them. This supposition might be called the parasite hypothesis or Red Queen hypothesis as it relates specifically to the evolution of sex.
Sex Chromosome Pairing and Fertility in the Heterogametic Sex of Mammals and Birds
Christopher B. Gillies in Fertility and Chromosome Pairing: Recent Studies in Plants and Animals, 2020
There is scant information concerning the evolutionary relationships between the sex chromosomes of eutherian, metatherian, and prototherian mammals. While random (paternal or maternal) X-chromosome inactivation is found in the somatic cells of eutherian females,31 in marsupials, the paternal X is preferentially inactivated,32 thereby establishing a basic difference between these groups. Additionally, the meiotic behavior of the XY pair in marsupials is markedly different from that of eutherians (see Section VI). Prototherian mammals seem to have special sex-chromosome mechanisms.33 A general perspective on the evolution of sex chromosomes has been provided by Bull.34
An overview of sex and reproductive immunity from an evolutionary/anthropological perspective
Published in Immunological Medicine, 2021
Yoshihiko Araki, Hiroshi Yoshitake, Kenji Yamatoya, Hiroshi Fujiwara
Nevertheless, life on Earth must coexist with viruses, such as SERS-CoV-2, the cause of the recent pandemic [42]. Viruses may be at odds with life and are clearly not mutually beneficial. This can be said to be an everyday phenomenon in terms of the geological time scale. Before the emergence of sex, eukaryotic cells developed via symbiotic relationships with prokaryotes that became intracellular organelles, according to the endosymbiotic theory [43–45]. Specifically, mitochondria and chloroplasts were derived from aerobic bacteria and cyanobacteria, respectively. Eukaryotes, such as plants and animals, then evolved to undergo sexual reproduction. Furthermore, mammals developed a reproductive strategy that exploits the immune system by acquiring an unusual organ called the placenta, which is possibly the result of a virus being lodged in a mammalian ancestor. What is the destination of human prosperity and evolution through sexual reproduction? If we consider these issues from the perspective of both human cultural and biological histories, we may be able to see a slightly different side to the common sense of the past.
Clinical features and incidence trends of amyotrophic lateral sclerosis in Navarre, Spain, 2007–2018: a population-based study
Published in Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration, 2021
Ivonne Jericó, Itsaso Elizalde-Beiras, Inmaculada Pagola, Laura Torné, Arkaitz Galbete, Josu Delfrade-Osinaga, Esther Vicente
Joinpoint analysis for global incidence experienced unstable annual rates during the whole period, showing an upward trend with a statistically significant slope (Figure 2(a)). Regarding the IRs evolution by sex, Joinpoint showed a change-point in 2015 for women, with a slightly decreasing slope until that year but with an increasing slope from 2015 onwards, which is not statistically significant. The IRs trend for men is significantly upward for the entire studied period (Figure 2(b)). And regarding age-groups, trends seem stable except for the group aged 70–79, which showed a statistically significant increasing slope (Figure 2(c)). In fact, only women aged 70–79 showed an important increasing trend, which is statistically significant (Figure 2(d)).
Sexual satisfaction improvement in patients seeking sex therapy: evaluative study of the influence of traumas, attachment and therapeutic alliance
Published in Sexual and Relationship Therapy, 2023
Anne-Julie Lafrenaye-Dugas, Martine Hébert, Natacha Godbout
A second objective of this exploratory study was to document the overall sexual satisfaction evolution of sex therapy patients through the course of treatment. Our hypothesis was that sex therapy would increase the patients’ overall level of sexual satisfaction. The results show that between the pre-test and the post-test, on average, patients report an improvement in their level of sexual satisfaction. Therefore, the sex therapy treatment they received appears as an efficient solution to improve their level of sexual satisfaction.
Related Knowledge Centers
- Animal
- Eukaryote
- Evolution
- Multicellular Organism
- Sex
- Sexual Reproduction
- Phylogenetic Tree
- Common Descent
- Species
- Isogamy