Why are acentric chromosomes genetically inactive?

Acentric chromosomes are formed as a result of inversion of genes in one of the chromosomes in a homologous pair. This is a type of chromosomal aberration. Homologous loci are paired at meiosis. The meiotic anaphase will contain a chromatid connecting the two centromeres, called a chromatid bridge; a chromatid lacking a centromere altogether is called an acentric fragment. Neither of these behaves normally in cell division and both are eventually lost. The only viable products of meiosis in inversion heterozygotes are the chromatids that underwent no crossing over within the inverted section. Thus, the acentric chromosomes are genetically inactive due to absence of centromere.