S17 - S1.Zickler was the first person to demonstrate gene...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
S1.Zickler was the first person to demonstrate gene conversion by observing unusual ratios in Neurospora octads. At first, it was difficult for geneticists to believe these results because they seemed to contradict the Mendelian concept that alleles do not physically interact with each other. However, work by Mary Mitchell provided convincing evidence that gene conversion actually takes place. She investigated three different genes in Neurospora. One Neurospora strain had three mutant alleles: pdx-1 (pyridoxine-requiring), pyr-1 (pyrimidine-requiring), and col-4 (a mutation that affected growth morphology). The pdx-l gene had been previously shown to map in between the pyr-1 and col-4 genes. As shown here, this strain was crossed to a wild-type Neurospora strain. pyr-1 pdx-1 col-4 ± pyr-1 + pdx-1 + col-4 + She first analyzed many octads with regard to their requirement for pyridoxine. Out of 246 octads, two of them had an aberrant ratio in which two spores were pdx-1 and six were pdx-1 + . These same spores were then analyzed with
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 2

S17 - S1.Zickler was the first person to demonstrate gene...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online