Final answer:
The statement is true; genes are mixed and rejoined in each generation due to the processes of meiosis, independent assortment, and recombination, as opposed to the obsolete blending theory which suggested a permanent blending of traits.
Step-by-step explanation:
Genes are indeed mixed and rejoined every generation, a concept fundamental to our understanding of genetics. During the process of meiosis, chromosomes are shuffled and recombined to create genetic diversity. The offspring result not from a blending inheritance, where traits are forever merged, but from a process in which individual genes can be tracked through generations. This is due to the phenomena of independent assortment and recombination.
Thomas Morgan's observation of fruit fly traits with a recombination frequency of 17% illustrated that genes on the same chromosome do not always sort together into gametes. Moreover, Alfred Sturtevant's work with gene mapping reinforced the understanding that genes can be linked or unlinked with varying recombination frequencies, affecting how they are passed down to offspring. Furthermore, processes such as crossing over during meiosis allow genes that are further apart on the same chromosome to assort independently due to the increased likelihood of recombination occurring between them.
It should also be noted that phenomena such as genetic drift and gene flow can accelerate the spread of new alleles throughout a population, further diversifying genetic makeup. Altogether, gene recombination is the cornerstone for the remarkable genetic variation observed in populations, distinguishing the modern understanding of genetics from the obsolete blending theory of inheritance.