Chordata Arised in An Unstable Environment: Hypothesis Volume 58- Issue 1

AV Makrushin*

• ID Papanin Institute for Biology of Inlamd Waters Russian Academy of Science, 152742, Borok Yaroslavskaya obl, Russia

Received: July 25, 2024; Published: August 02, 2024

*Corresponding author: AV Makrushin, ID Papanin Institute for Biology of Inlamd Waters Russian Academy of Science, 152742, Borok Yaroslavskaya obl, Russia

DOI: 10.26717/BJSTR.2024.58.009083

Abstract PDF

Previously, a hypothesis was proposed according to which the evolutionary predecessor of a malignant tumor was the early somatic embryo of the first Metazoa on Earth preparing for diapause, and the resorption of this embryo was the evolutionary predecessor of tumor regression. The resorption of the embryo preparing for diapause in the first Metazoa on Earth occurred because they lived in an unstable environment. Tumor regression has been described in humans. Because the resorption of this embryo in them was an evolutionary precursor to tumor regression. human tumor regression suggests that Chordata arose in an unstable environment.

Keywords: Cancer; Modular Invertebrates; Diapause

The body’s physiological regulation system is multistage. It is built on a hierarchical principle. It was formed in the course of evolution through the development of increasingly effective and economical compensatory and adaptive mechanisms. The wasteful and ineffective morphogenetic mechanisms of ancient adaptive reactions lost their activity, but their program in the genome was preserved. It is implemented in pathological situations. In the dynamics of pathological processes, one should see not an arbitrary disruption of structures and functions, but a natural retreat into the past stages of evolution and the exposure of ancient regulatory physiological mechanisms leading the hidden activity. The evolutionary predecessors of many pathological processes were the processes of normal ontogenesis of ancestors (Orbeli [1]). There is a rare mental illness called narcolepsy. It lies in the fact that in the most unsuitable conditions for sleep, for example, when driving a car, an irresistible fall asleep occurs. The dream may last minutes, hours, days or months. The evolutionary predecessor of narcolepsy was probably hibernation (Karmanova, et al. [2]).

If this assumption is true, then our ancestors, when they became vertebrates, lived in a seasonal climate. What can regression of a malignant tumor say about the habitat of our ancestors? What process of normal ontogenesis of our ancestors was its evolutionary predecessor? Which of our ancestors had it? The purpose of this article is to discuss these issues. Tumor regression is its resorption without the use of therapeutic agents. Before discussing the questions posed, it is necessary to answer the question of which of our ancestors the process of normal ontogenesis was the evolutionary predecessor of cancer and what kind of process they had. The mutation theory of cancer does not answer this question. Here is another explanation for the nature of this disease. Cancer has been described in representatives of all groups of Metazoa (Krieg [3]). This suggests that the evolutionary predecessor of cancer should be sought in the species that were at the base of all phylogenetic groups of Metazoa. There is an assumption that the first Metazoa on Earth, from which all modern species originated, were colonial sessile invertebrates (Jӓgersten [4]). Modern colonial sessile species are Spongia, Cnidaria, Bryozoa, Pterobranchia and colonial Ascidiacea. Some of these invertebrates enter diapause before the seasonal deterioration of the environment.

Preparation for diapause occurs in a similar way and only in a characteristic way for them. It consists in the fact that all actively functioning zooids of the colony die off. But before dying, zones are formed in them, the cells of which dedifferentiate and begin to reproduce, forming diapausing somatic embryos (Ivanova Kazas [5]). In Spongia they are called gemmules, in Cnidaria - podocysts, in Bryozoa- statoblasts, in Pterobranchia and colonial Ascidiacea - resting buds. If the first Metazoa on Earth were truly sessile and colonial, then, probably, early somatic embryos served to survive the unfavorable season, and all actively functioning zooids died when the colony entered diapause. Therefore, how the first Metazoa on Earth prepared for diapause can presumably be judged from the results of studying this process in modern sessile colonial invertebrates. Let us compare the processes occurring in the body during cancer with the processes occurring in the listed invertebrates during the transition to diapause. A comparison shows that these processes are similar. The similarities are as follows.

1. Cancer begins with the appearance in the body of a zone whose cells become malignant (malignization of cells is their dedifferentiation). The formation of diausing embryos in the listed invertebrates also begins with their dedifferentiation.

2. In cancer, malignant (dedifferentiated) cells multiply. During the formation of diapausing embryos in the listed invertebrates, dedifferentiated cells also multiply.

3. Cancer ends with the death of the body.

The transition to diapause of the listed invertebrates will also end with the death of all zooids of the colony. This similarity gives grounds to assume that the evolutionary predecessor of cancer was the process of transition into diapause of the first Metazoa on Earth, and the tumor is an atavistic early somatic embryo of the first Metazoa on Earth preparing for diapause. If a tumor is truly an atavistic early somatic embryo preparing for diapause, then its regression is the evolutionary precursor of this process in humans (Makrushin [6]). In the first Metazoa on Earth, did the somatic embryos preparing for diapause dissolve and, if so, why? Metazoa originated in the World oceans. In it, if the water area is located in a seasonal climate zone, the alternation of favorable and unfavorable periods for life is subject to a strict seasonal rhythm. Living conditions here are stable. There are few species that enter diapause here, but if they do, then there is no need to develop the ability, having begun preparation for diapause, to stop it and return to active life. Living conditions in water areas (bays, estuaries) partially or completely separated from the World Ocean are not stable. Due to the smaller volume of water than in the World Ocean, they are susceptible to the influence of accidents, such as weather.

The populations living here, in preparation for experiencing an unfavorable period for life, need to be prepared both for the upcoming severe deterioration of the environment, and for the fact that the deterioration of the environment will be weak and can be survived in an active state. Staying in diapause under favorable conditions for life threatens the population with its displacement from the ecosystem. To prevent this from happening, some of the individuals in the population, having begun preparation for diapause, must stop it by resolving the embryos preparing for diapause. This allows the population to survive if the deterioration of the environment is weak and can be survived in an active state. If the resorption of embryos preparing for diapause in the first Metazoa on Earth indicates that they lived in an unstable environment, then regression of the tumor in humans gives reason to assume that our earliest ancestors, who became Chordata, originated in an unstable environment. I do not know any information about tumor regression in representatives of other classes of Metazoa. Therefore, I cannot assume anything whether their distant ancestors lived in stable or unstable conditions.

1. Orbeli LA (1969) On the relationship between evolutionary physiology and medicine. LA Orbeli Selected works in 5 volumes. [O vzaimootnosheniyakh e`volyuczionnoj fiziologii i medicziny` // LA Orbeli Izbranny`e trudy` v 5 tomakh]. V1, M, LS 1: 246-255.
2. Karmanova IG, Oganesyan GA (1994) Physiology and pathology of the sleep-wake cycle (evolutionary aspects) [Fiiologiya i patologiya czikla bodrstvovanie-son (e`volyuczionny`e aspekty`)] SPb Nauka, pp. 196.
3. Krieg K (1973) Invertebraten in der Geschwustelsforschung. Beitrӓge Krebsforschung Bd Dresden Verlag T Steinkopf 12: 215.
4. Jӓgersten G (1972) Evolution of the metazoan life cycle. A comprehensive theory L NY: Acad Press, pp. 282.
5. Ivanova Kazas OM (1977) Asexual reproduction of animals [Bespoloe razmnozhenie zhivotny`kh] L Izdvo LGU, pp. 239.
6. Makrushin AV (2011) Senescens and carcinogenesis as atavistic processes inherited from modular ancestors: a hypothesis. Advances in Gerontology 1: 45-49.