Take what Nietzsche says in 'Beyond Good and Evil';

"It cannot be effaced from a man's soul what his ancestors have preferably and most constantly done ...
It is quite impossible for a man NOT to have the qualities and predelictions of his parents and ancestors in his constitution, whatever appearances may suggest to the contrary.
This is the problem of race".
[BGE 264 'What Is Noble?']

What can we learn from this?
To Nietzsche it is IMPOSSIBLE to escape one's genetic inheritance.
Therefore, ignoble ancestors render one ignoble.
Ergo, Nobility cannot be drawn from the Mass.

"There is only Nobility of Birth, only Nobility of Blood".
[WP 942]

Nietzsche constantly maintains the Distance from his Higher Race and the Mass by talking of them as different SPECIES!;

"The conditions under which a strong and Noble SPECIES maintains itself are the REVERSE of those which govern the 'industrial masses', the shopkeepers .."
[WP 901]

Not only are they a separate species, but they reverse everything that is of the mass. The mass are miscegenated - therefore the Higher Species is the REVERSE OF THAT.
Ergo, the Higher Race is of Pure Blood.

Such Purity is nobility's project;

"Physiological Purification and strengthening; the New Aristocracy has need of an opposite against which it struggles ..."
[WP 953]

Again, note the words used - 'physiological (i.e., of the body) purification'.
Note also the use of 'opposite' ;- the Mass is impure ... therefore ...

"A fundamental, artificial and conscious BREEDING of the opposite type to the Herd".
[WP 954]

A Pure Breed versus an Impure Cross-Breed.


The Mass are like the iron base on which a gold trophy is fixed - they are both of different stuff;

"Main consideration: not to see the task of the higher species in leading the lower .., but the lower as a base upon which higher species performs it OWN tasks - upon which it can stand".
[WP 901]

There is no suggestion here of a common evolution - on the contrary, there is only PROFOUND separation. To recap; different species with different tasks and reversed valuations and considerations.

Nietzsche asserted in his first book that Prometheus was the typical Aryan hero.
He was also a model for his higher race who would be noble barabrians and blond beasts;

"There exists also the type of barbarian who comes from the heights: a species of a conquering and ruling nature in search of material to mould. Prometheus was this kind of barbarian".
[WP 900]

This higher Aryan, Promethean Race are not to be bred out of the ignoble mixlings of the Mass, of the Herd!
That idea is contrary to Nietzsche's philosophy!

This "new master type and caste" [WP 957] - Note the word 'caste'!
This caste is to "arrive" [WP 954];

"I write for a Species of Man that does not yet exist: for the 'Masters of the Earth' ".
[WP 958]