According to our knowledge, this is the first instance in which SCoT markers have been used to describe the genetic alteration brought on by gamma radiation in adult male and female L..
Due to the healthy proteins and minerals, they contain, locusts are utilized as edible insects; but, because of their horrible migration and the harm it is inflicting on food crops, governments are looking for ways to combat them. One of the most prevalent agricultural pests, the migratory locust, L., consumes a lot of grass and harms crops. People have been moving into Egypt in greater numbers since the late 1990s, mainly in the southwest and west. From 2015 to 2019, outbreaks happened in Sharq El-Owinat and Toshka (Moustafa 2019).
Gamma radiation is the most invasive type of radiation produced by both natural and man-made sources and is made up of uncharged ionizing particles (IAEA-TECDOC-1363, 2003). Depending on the radiation dose received, ionizing radiation's biological effects can change. Gamma radiation causes errors at numerous molecular levels, including DNA, chromosomal abnormalities, cells, and proteins. Double strand breaks (DSBs) of DNA are the most prevalent sign (Rhee et al. 2012).
Numerous biological effects of parental radiation exposure have been documented in laboratory studies. These effects include chromosomal inversions (Sykes et al. 2006; Zeng et al. 2006), mitotic recombination in foetal cells (Liang et al. 2007), point mutations (Liang et al. 2007; Schilling-Tóth et al. 2011), increased DNA strand breaks in sperm (Schindewolf et (Nomura 1990, 2006; Barber et al. 2002).
The results of the current study on the effects of gamma radiation on adult male and female L. migratoria migrotaria showed that irradiation led to a progressive, significant rise in mortality along with an increase in radiation dose. This is in agreement with previous studies which revealed that the mortality of insects was dependent on the dose of gamma radiation (Sayed and Zahran 2017; Kiran et al. 2019; Sayed et al. 2020). This may be explained by the findings of Kinipling (1955), who reported that exposure to ionizing radiation causes somatic damage that interferes with the biological functions of the insects and induces genetic dominant fatal mutation with eventual insect sterilization (Ahmed 1992). In addition, exposure to ionizing radiation reduces the lifespan of insects and may hasten age (Baxter and Blair 1969). Furthermore, the data exposed that adult males were more sensitive to gamma radiation than adult females. The estimated LD50 value for males and females were 33.94 and 51.55 Gy, and the LD95 values were 161.13 and 207.95 Gy, respectively. This outcome was in agreement with Datkhile et al. (2009) who specified that female Chironomus ramosus was more tolerant to gamma irradiation than males.
Herein, there was a genetic diversity between normal (un-irradiated) males and females as presented by the similarity index of SCoT 1, SCoT 4, and SCoT 15. Likewise, the present results revealed that gamma radiation caused changes in the DNA structure of males and females, which were apparent by different estimated similarities among the tested doses and the tested sexes after using SCoT 4.
The primary cause of the mutation load in living things is oxidative DNA damage (Von Sonntag 1987). Indirect action, which requires energy transfer from another molecule, and direct action, which ionizes the target molecule directly, are the two ways that ionizing radiation can alter biochemistry. These mechanisms are well-defined in biological systems where water is a key component. Proteins, carbohydrates, lipids, and enzyme molecules make up the biological system of an insect's essential nutrients. Any alteration to this component consequently has an impact on the biological system and adult functioning (El-Naggar 2009).
Although the residual-radionuclides have a low dose rate, the cumulative dose over time is likely to cause oxidative stress in exposed organisms, DNA damage, and an accumulation of unrepaired mutations (Bonisoli-Alquati et al. 2010a; Einor et al. 2016); and epigenetic effects that may amplify the effects of changes in DNA sequence (Kovalchuk and Baulch 2008; Ilnytskyy and Kovalchuk 2011).
Gamma-radiation caused some bands to appear and others to disappear throughout our investigation, resulting in variances in SCoT-PCR patterns across the various samples. In line with Hamed et al. (2009), El-said (2013), Rizk et al. (2017), Zahran et al. (2017), and Ali et al. (2018). Single and multiple strand breaks, point mutations caused by -rays, changed or oxidized bases, and band loss may all be associated with band loss (Esnault et al. 2010). The formation of new bands may be caused by variations in oligonucleotide primer sites as a result of DNA changes and other mutations (Dhakshanamoorthy et al. 2011).
Additionally, the outcomes of this research may be attributed to the fact that irradiation enhances the production of reactive oxygen species (ROS). Numerous biological processes, including the cell cycle, programmed cell death, development, and reproduction, are regulated by ROS, which affects gene-expression and transcription (Sarvajeet and Narendra 2010). Furthermore, it causes histones to separate from the chromatin strands (Volle and Dalal 2014). As a result of exposure to ionizing radiation, enzymes needed for DNA synthesis and repair, such as DNA polymerase, become inhibited. This could happen as a result of chance DNA-protein binding (Stobbe et al. 2002, Chalmers et al. 2010).
The recorded difference in female and male mortality by gamma radiation was clarified by the difference in generated fragments by SCoT-PCR. That variance might be due to the basic difference between the germ cells of males and those of females besides the genetic variation between them, therefore, they vary in their response toward gamma radiation (Limohpasmanee et al. 2017).