Question
This ratio of four phenotypes is skewed to 15-to-1 for duplicate genes and to 13-to-3 under dominant suppression. For 10 points each:
[10h] Give the four-term ratio of phenotypes that, in Mendelian genetics, arises from a dihybrid cross of parents that are both heterozygous for two genes that cause independent phenotypes.
ANSWER: 9-to-3-to-3-to-1 [accept numbers in any order]
[10m] The 9-to-3-to-3-to-1 ratio is skewed by this most common exception to the law of independent assortment. This phenomenon is measured in centimorgans.
ANSWER: genetic linkage [reject "linkage disequilibrium"]
[10e] Linkage is a driver of linkage disequilibrium, which is measured with this quantity. In statistics, large values of this quantity are often misinterpreted as implying causation.
ANSWER: correlation [or correlation coefficient; prompt on r; prompt on r-squared or coefficient of determination]
<Science - Biology>
Data
Summary
| Tournament | Edition | Exact Match? | Heard | PPB | Easy % | Medium % | Hard % |
|---|---|---|---|---|---|---|---|
| 2025 PACE NSC | 06/07/2025 | Y | 36 | 16.39 | 94% | 31% | 39% |