DNA-repair capacity assay: Oocyte repair of mutagenized sperm.

<p>(A) Crossing scheme of the experiment. Only the genotype of the first pair of chromosomes (<i>X/Y</i>) is shown. Parental females (F0) from either UV resistant or sensitive lines (<i>i</i>.<i>e</i>. lines from the tails of the UV sensitivity index from the latitudinal screen) were mated to an F0 Parental male carrying an <i>FM7a</i> balancer X chromosome with <i>B</i>^<i>1</i> as a visual marker (Bar eyes). As those males were fed with a mutagen (MMS), they produced gametes that carried deleterious DNA lesions on the <i>FM7a</i> chromosome (<i>FM7a*</i>), some of which may be repaired by the oocyte cytoplasm. F1 daughters were then mated to their F1 brothers. F2 offspring were scored for sex and presence of <i>FM7a*</i>. (B) Estimation of DNA damage repair capacity across lines showing higher <i>vs</i>. lower embryo UVB sensitivity. The graph shows the mean proportion of recovered offspring (± s.e.m.) carrying mutagenized (<i>FM7a*</i>) chromosomes from a crossing scheme initiated with grandmothers (F0) from either the 14 least sensitive (<i>i</i>.<i>e</i>., most resistant) or the 13 most sensitive lines. The recovery rate was significantly greater for the less sensitive (<i>i</i>.<i>e</i>., more resistant) lines (Mann-Whitney U test: <i>p</i> = 0.0017).