How has this biotechnology harmed the Texel sheep?

loss of genetic diversity  

Explanation:

Artificial selection, also known as selective breeding, refers to the identification by humans of desirable phenotypic features (traits) in plants and animals and the subsequent breeding procedures to enhance and perpetuate these traits in offspring. As a consequence of artificial selection, future generations of selectively bred animals/plants will share favorable gene variants (alleles), thereby genetic diversity will decrease in the population. This reduction in the gene pool will affect genetic progress and consequently also breeding programs in the future.