The subtopic in the middle and four tasks round it: label a diagram, complete a table and fill 9 gaps. Every box rests on a learning objective of the topic in the AP Biology course and exam description. Type into the blanks and check them, or print it on A4, Letter or A3 with an answer key.
Paper
Each subtopic on a landscape page, as shuffled and chosen on screen.
Topic 5.4
Non-Mendelian Genetics
AP Biology · Unit 5 Heredity
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Name
5.4.APatterns that depart from Mendel
Pattern
What happens
Example
heterozygote is intermediate
red × white snapdragon gives pink
both alleles are fully expressed
AB blood type
Sex linkage
the gene is on the X chromosome, so males show a recessive allele more often
red-green color blindness
Polygenic
many genes add up to one trait, with a continuous range
height, skin color
Epistasis
one gene masks the effect of another
coat color in Labrador retrievers
Pleiotropy
one gene affects several traits
sickle cell allele
Cytoplasmic
organelle DNA is passed on by the mother's egg
mitochondrial and chloroplast genes
5.4.AGenes on one chromosome
Two genes close together on the same chromosome are and tend to be inherited together, so a cross does not give the 9 : 3 : 3 : 1 ratio. Crossing over can separate them, and the further apart two genes are, the more often it does. Recombination frequency, the percent of offspring that are recombinants, is therefore a measure of distance: 1% is one map unit. A gene on the X chromosome shows up more often in males, who have only one X.
Topic 5.4Non-Mendelian Genetics
5.4.AIncomplete dominance
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5.4.ATesting a ratio
A chi-square test compares the observed counts with the counts expected from a hypothesis. For a 3 : 1 cross with 400 offspring (290 dominant, 110 recessive), the expected counts are 300 and 100. χ² = Σ(o − e)²/e = 100/300 + 100/100 = . With one degree of freedom, 1 for two phenotypes, the critical value at p = 0.05 is 3.84, so the result is significant and we fail to reject the hypothesis that the cross gives a 3 : 1 ratio.
Word bank1.33CodominanceheterozygoteIncomplete dominanceincomplete dominancelinkednotred homozygotewhite homozygote
Answer key
Every box on the sheet with its gaps filled in, as the subtopic reads in full.
LabelIncomplete dominance
red homozygote
heterozygote
white homozygote
incomplete dominance
TablePatterns that depart from Mendel
Pattern
What happens
Example
Incomplete dominance
heterozygote is intermediate
red × white snapdragon gives pink
Codominance
both alleles are fully expressed
AB blood type
Sex linkage
the gene is on the X chromosome, so males show a recessive allele more often
red-green color blindness
Polygenic
many genes add up to one trait, with a continuous range
height, skin color
Epistasis
one gene masks the effect of another
coat color in Labrador retrievers
Pleiotropy
one gene affects several traits
sickle cell allele
Cytoplasmic
organelle DNA is passed on by the mother's egg
mitochondrial and chloroplast genes
GapsGenes on one chromosome
Two genes close together on the same chromosome are linked and tend to be inherited together, so a cross does not give the 9 : 3 : 3 : 1 ratio. Crossing over can separate them, and the further apart two genes are, the more often it does. Recombination frequency, the percent of offspring that are recombinants, is therefore a measure of distance: 1% is one map unit. A gene on the X chromosome shows up more often in males, who have only one X.
GapsTesting a ratio
A chi-square test compares the observed counts with the counts expected from a hypothesis. For a 3 : 1 cross with 400 offspring (290 dominant, 110 recessive), the expected counts are 300 and 100. χ² = Σ(o − e)²/e = 100/300 + 100/100 = 1.33. With one degree of freedom, 1 for two phenotypes, the critical value at p = 0.05 is 3.84, so the result is not significant and we fail to reject the hypothesis that the cross gives a 3 : 1 ratio.
Biology by Bradford