Meiosis — non-disjunction can put an extra copy of a chromosome into gametes
“Few candidates recognised that errors in meiosis could result in the doubling up of a single chromosome seen in all three sets of chromosomes.”
Compare normal separation with non-disjunction. Watch how a failure to separate sends an extra chromosome into a gamete, leading to three copies after fertilisation.
The extra whole chromosome comes from a separation error in meiosis — not from mutation, crossing over, or normal assortment.
Original reconstruction inspired by the misconceptions described in the Singapore-Cambridge GCE A-Level H1 Biology 8876 November 2023 Examiner Report. Not the actual examination question. For classroom exploration.
Made by lookang, using Claude Fable 5. More resources: iwant2study.org