Hunting the Exemplar Cleft Gene: Linkage to 1q32
Take the reading one piece at a time. For each piece: read it once, underline the sentence that says what happens, then look up any word in the list. Tap a word to see its definition.
Piece 1 of 2
A DNA marker is a spot in the genome that varies between people and is easy to read, like a numbered signpost. It is NOT the disease gene; it is a known address you can track, like a mile-marker on a highway. When two spots are close on a chromosome they tend to travel together through generations, which is linkage; when far apart or on different chromosomes they get shuffled independently.
Piece 2 of 2
This next family is NOT Mateo's. It is a large Van der Woude family where clefting and lip pits run as a clean dominant trait, the kind scientists use to corner a cleft gene. You genotype three markers, M-A near chromosome 8, M-B near chromosome 1 band q32, and M-C near chromosome 4. Across the affected members (an affected grandfather, mother, uncle, and son) every one carries M-B version 7, while no unaffected person (the married-in father, grandmother, daughter) carries version 7. The chromosome 8 and chromosome 4 markers are mixed among the affected people. Family co-segregation of this kind, plus linkage to chromosome 1q32-q41, is how the Van der Woude gene was first localized.
Reading the Research
- Skim the title and abstract first to get the gist.
- Circle the one sentence that states the main claim.
- Box the evidence the authors give for that claim.
- Mark one sentence that confuses you, and move on.
Now put it together: In one or two sentences, say what this whole reading is telling you about Mateo. Then go back to the lesson and fill in the guided notes.