Small, inbred populations: Which statement is NOT generally true about the genetic consequences of inbreeding in small populations?

Introduction:
Small, inbred populations experience characteristic genetic changes. Distinguishing which outcomes are driven by inbreeding and drift versus those that reflect altered mutation processes is important in conservation genetics and medical genetics. This question asks you to identify the statement that is not generally true.

Given Data / Assumptions:

• Inbreeding increases the probability that alleles are identical by descent.
• Small population size magnifies genetic drift.
• Mutation rate is primarily a molecular property and not directly altered by mating structure.

Concept / Approach:
Inbreeding raises homozygosity, exposing deleterious recessive alleles and increasing recessive disease incidence. In small populations, drift can randomly fix or lose alleles, reducing overall genetic diversity. However, the per-base mutation rate is not inherently increased by inbreeding; new mutations arise largely independently of mating patterns, although their fate in the population is influenced by drift and selection.

Step-by-Step Solution:

Verification / Alternative check:
Pedigree analyses and population-genetic models show increased homozygosity (and disease) with inbreeding without necessitating any change to the underlying mutation rate μ; instead, μ influences the supply of new alleles, not their immediate frequency under inbreeding.

Why Other Options Are Wrong:

• Loss of diversity and allele fixation: classic outcomes of drift in small populations.
• Increased recessive disease: consequence of homozygosity revealing deleterious alleles.
• Elevated homozygosity: the defining genetic signature of inbreeding.

Common Pitfalls:
Attributing increased disease to a supposed rise in mutation rate; the driver is exposure of existing recessive alleles through homozygosity.

Final Answer:
Mutation rate is increased as a direct result of inbreeding