After the destruction of Atlantis around 23,000 years ago and the Ice Age caused by it that ended about 11,000 years ago, our civilization had difficulty recovering. The humanity was fractured, and the remaining tribes were stuck in a very low vibrational level of life. Various alien races contributed their genetics to boost the development of our civilization. As a result, the modern Homo sapiens was created and has evolved as a hybrid between the Earth humans and the aliens. We are told that humanity is comprised of about 22 total alien races. It's not clear in which order the hybridization happened. Most likely, each of the modern human races was created by different aliens by hybridizing the DNA of Earth humans and galactic humans. Since then, these races and tribes intermixed and intermingled, creating the modern homo sapiens.
The main races who contributed their genetics to modern human are: Lyrans, Pleiadians, Yahyel, Orions, Sirians and Annunaki (Tall Whites with human-reptile-insectoid genetics). Other races that likely have contributed to our genome are Reptilians, Andromedan Humans, Martians, Non-Zeta Greys, Zeta-Greys, Fendorians, Arcturians, Ubsilo and otherworldly races from our planet: Sasquatch and Agarthans. Elohim are also are mentioned in the Bible, these are likely higherdimensional humans (literally, the ones who came from the sky), who were genetic engineers which created the modern homo sapiens. It is unclear whether Elohim contributed their genetics. So, at this point, most of the humans on Earth are descendants of all the races that contributed to the homo-sapiens. There were times on earth when the population was very small. Since the growth of the population, wars and migrations, most of the human genes have been mixed pretty thoroughly among the earth's population although there remains a few isolated populations which don't intermix with others.
In the old times, the aliens openly visited the earth and were worshipped by humans as gods. In more recent times, the aliens were perceived as supernatural and fairy tale beings, which essentially, they are, since they are from other dimensions. Their hybridization with humanity has never stopped. The alien genes were infused into humans in all times in every century. Some of these infusions were via genetic manipulation and sometimes galactic humans would find refuge on Earth and establish families with Earth humans.
Some of the alien settlers taught us technology, art and philosophy. Some of them became priests and teachers. Many of the talented people of the recent past came from the alien bloodlines. In recent times, in 1954, the hybridization program by the aliens received a boost as the aliens obtained permission for the program from some of the Earth's governments. This was done by an alliance of Zeta-Greys, Reptilians and Orions who negotiated with the some of the secret services of mainly English-speaking governments, the secret rights for hybridizing their population. This was done in exchange for alien technologies such as propulsion, free energy, teleportation and mind control technologies. Soon, both parties violated the the agreement making it ineffective. Nonetheless, the aliens continued the hybridization program.
At certain stages, the hybridization program was run jointly by the negative aliens and negative humans. Civilians were abducted and subjected to alien medical procedures, examinations and hybridization. The abductors were the negative humans, Reptilians, Orions, Tall-Greys and Short-Greys, working in the same facilities. Some of the facilities were on Earth and some of the facilities were off-planet.
For the first 50 years until about 2005, the hybridizations were traumatic for the humans, since many of the aliens and the humans who worked in the hybridization program were rough and treated the abductees poorly. The initial failure rate with hybridization was high, so many hybrid children were deficient. The initial purpose of the hybridization was also negative. The Zeta-Greys and the Reptilians created the hybrid people and infused the hybrid DNA back into the humans on Earth, thus creating hybrids on Earth who are unaware of the hybridization.They also used implants to track their hybrids on Earth, and possibly for mind control. The overall purpose of hybridization was to take over control of the Earth. The Zeta Greys are known in the Galaxy for their sneaky tactics of taking over other civilizations: they use time manipulation and transdimensional travel to quietly infuse the planet's population with Zeta genes - this makes the new hybrids prone to mind control by the Zetas which use it to take over the control of the planet.
As far as I know, this plan was stopped around 2006-2010. The alliances that are friendly to humanity - The Galactic Federation of Light, Girk-Fitneer and the Ashtar Command - increased their protective military presence in the Solar system and forced the negative Zeta-Greys, Orions, Annunaki and other Reptilians to leave the solar system. Since that time, the Earth has been protected from the takeover attempts. Until that time, the Reptilians and Orions controlled the top of our military and financial sectors. Now that the negative aliens have been expelled, mainly Earth humans remain in control of these sectors.
Although the hybridization program was done with negative purposes and means, it has still produced some positive results. It produced some hybrid human-alien bloodlines which possess advanced telepathic and psychic abilities and better compatibility with the 4th density. Also, new human-alien hybrid races (such as Shakani) have been created and seeded in other locations in the galaxy. These hybrid races, live in the 4D and enjoy the riches of galactic cultures. Many of the new hybrid races are friendly to the humanity and eager to help our civilization as advisers.
In addition to the negative hybridization program, there was also a positive voluntary hybridization program carried out by the friendly advanced aliens who only wanted to help us. They would establish a friendly relationships with human individuals, take them for the visits to their ships and planets and invite them to help their hybridization program on voluntary basis. These positive races included Pleiadians and Yahyel.