There is a song in the comedy “The Stupids”, entitled “I’m My Own Grandpa”, which details how (when written in a family tree) one can be their own grandfather, without any incest.
However, since dogs don’t marry, dog breeders usually do it in the “home-made sin” way – they breed a grandson to his grandma or a grand-daughter to her grandpa. Some purebred dog breeders also breed mother to son, father to daughter, uncle to niece, aunt to nephew, cousin to cousin.
This completely negates the whole plan of life on Earth. How can someone be a dog breeder and not have heard about the birds and the bees? (The “bee” part is about how plants pay bees with nectar, to transfer pollen from one plant to another so to prevent inbreeding.)
Many plants can reproduce vegetatively, the plant just grows a root like ‘stem’ sideways (horizontal) along the ground, and then a new plant grows from one of the nodes of this ‘stem’. Once the new plant gets established, the ‘stem’ can be cut, and both plants do fine (they do fine even if the ‘stem’ is never cut).
It is said that moving armies would, each night, cut stakes from olive trees and drive the stakes into the ground so that they could tie their horse’s rope where the horses could graze during the night. The stakes (cut branches) took root, and rows of wild olive trees were the result.
Of course, there had to be some olive trees there already to cut the stakes from, but the story does illustrate one way that plants can reproduce vegetatively. Plants can clone themselves very easily, so why do they also go to the bother of making flowers and setting seed? Not only that, but the newer species of plants are the ones most likely to have methods to prevent inbreeding (like having male and female flowers on different plants).
Many plants have flowers that are both male and female all in the same flower (called “perfect”). Like if you look at a rose flower, the center is the female part, and surrounding it are several male parts which make pollen (plant sperm). The female part of the flower makes a nectar (honey) which attracts bees. The bees get dabbed with pollen at each flower, and so unwittingly pollen in transferred from one rose to another so as to prevent inbreeding (incest).
Other plants separate the genders more, like corn plants. The corn plant makes female parts (the corn ‘ears’) which grow off the sides of the corn plant, well after the ears are ripe enough to become impregnated by pollen, the top of the plant produces tiny plain flowers that produce its own pollen.
Why don’t the pollen flowers grow closer to the ears? So that the wind can bring pollen from a different plant. The plants with the male and female parts of the same plant closer together, produced inbred seeds and did not survive as well as the plants with less inbred seed.
Other types of plants have some individual plants that are male and other individual plants that are female (like with animals). Mulberry trees are either male (and produce little flowers on tiny stems that look like caterpillars), or female and produce purple mulberry fruits.
Because these fruits are then eaten by birds, and then the bird dropping stain things purple, female mulberries are sometimes banned by some cities. Male plants are sometimes banned by cities because pollen (plant sperm) often floats through the air and gets into people’s noses when they inhale, and causes allergies.
Why am I telling you this? I am trying to point out the nature goes to great lengths to prevent inbreeding or to the reduce the amount of inbreeding.
Stallions chase off the young colts, then the colts can not bred to their mother, sisters, or aunts. The young colts must roam around until they are old enough to get their own harem of mares. Because they have traveled far, the mares they get are less likely to be related to them. The species of animals that became too inbred sometimes died off.
The plan of nature, goes to great efforts to avoid inbreeding. Then along comes the “purebred” breeders who act like they know a better way than nature, and they divide dogs into separate little gene pools, that they call “breeds” and they inbred dogs to “set” type (make all the puppies look-alike by removing genetic variation. Genetic variation is the whole point of nature’s using flowers and bees, and having two genders in animals.