It's just that they were both classified as low-rank Saiyans at birth so they both have similar features. So that's pretty much why they look the same. As for personality, like I said before Turles was designed to show what Goku would be like if he never bumped his head and became good.
In fact, the two of them technically aren't even related by blood. Turles himself even addresses their similarities. According to Turles, both he and Goku were born into a low social class among Saiyans. Because of this, they were genetically pre-determined to have similar facial structures and physical appearances.
In the Dragon Ball Z: Anime Film Comics, it is stated that the reason why Turles and Goku look alike is that the facial patterns of each warrior are similar within the low-rank Saiyans.
Turles is the first evil version of Goku to appear, the second being Shadow Goku from Dragon Ball Heroes and the third being Goku Black from Dragon Ball Super.
The more official reasoning for Turles' visage is that, as a low-caste Saiyan, he was genetically predisposed to look like Goku, as there isn't much genetic diversity among their ranks. RELATED: Why Didn't King Kai Teach the Kaio-ken to Other Z Fighters?
Raditz (ラディッツ, Radittsu), also known as "Raditz the Runt", is a mid-class Saiyan warrior, the older brother of Goku and the eldest son of Bardock and Gine. He is one of the few remaining full-blooded Saiyans left alive after his homeworld was destroyed.
Five years later, Goku meets his evil older brother Raditz and learns about his heritage. Goku comes from a race of nearly extinct extraterrestrials called Saiyans, himself having been sent from their home planet to prepare Earth for sale on the intergalactic market by destroying all its life.
The story takes place between the 10 year gap of the Majin Buu events and when Goku turns into a Grandpa. Golene is Goku's long lost sister. Her Saiyan name was Kakarotte but her storyline of how she turned to the good side was far different from Goku's.
Born on the same day as Kakarot (Goku), the two Saiyan babies lie side by side in the nursery. Goku struggled with his low power, wailing and crying continuously. Broly, on the other hand, was born with immense natural power, and baby Goku's display of weakness drove him mad.
In Super Dragon Ball Heroes: Ultra God Mission, Goku and Bardock finally fight each other, with Bardock surprisingly proving to be more powerful than ever before.
After Turles becomes more powerful with the fruit from the Tree of Might, Goku uses the Kaio-ken x10 (Kaio-ken x20 in the Funimation dub) to attack him but is still unable to keep up.
While status was determined by power-level -- and there were cases of some low-level fighters having higher power levels than others -- most of the lower-class Saiyans did not achieve this. This is why Goku looks like Bardock and Vegeta looks like his father, as if they were copy-pasted into existence.
There last surviving members of the Saiyan Army, Prince Vegeta and the low-class warrior Goku would face off in a battle that would alter the course of history both for Earth and the Saiyan race.
Dragon Ball's Goten has always been a powerful warrior and has proven time and time again that he is just as strong, if not stronger than his elder brother Gohan. With his seemingly limitless potential and eagerness to fight, it's very possible that Goten could end up becoming the most powerful Saiyan ever.
Xicor is also known as Zaiko (ザイコー Zaikō) is the main antagonist in Toyble's Dragon Ball AF manga and makes appearances in the Dragon Ball Absalon manga and series. He is Goku's genetically created son by West Kaioshin, making him half Saiyan and half Shinjin.
25, but physically 24, when he returns to Earth after killing Frieza. 28, but physically 27, during the Android and Cell Sagas. 35, but physically 27 (since he was dead for another 7 yrs), in the Buu saga. Then 45, with a 37 yr old body at the epilogue of the Dragon Ball Z series.
Broly awakens in a rage upon hearing Goten (Goku's youngest son) crying. While Trunks distracts Broly, Gohan arrives, and he and Goten are able to fight back. The Dragon Balls summon the spirit of Goku, who joins his sons to perform a family Kamehameha attack which launches Broly into the sun, destroying him.
Vegeta (Japanese: ベジータ, Hepburn: Bejīta) (/vəˈdʒiːtə/ və-JEE-tə), fully referred to as Prince Vegeta IV (ベジータ 王子 四世, Bejīta-ōji Yon-sei), is a fictional character in the Japanese franchise Dragon Ball created by Akira Toriyama.
According to the information available online, Broly generally stands at 6' 1” in his regular form and becomes between 9' 0” and 9' 10” in his Legendary Super Saiyan form.
In film itself Turles comments on the resemblance and says it's because he and Goku are both low-class Saiyans, who lack distinctive physical traits. Bear in mind it is non-canon of course, 'cause Raditz don't look like Goku. "Life lies ahead of you like a field of snow.
