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tenorsextets
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When doing a punnett square for 2 parents and their child's possibility of a trait, how many punnett squares do you do?
2, one for each possibility
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When doing a punnett square for genes or genotypes, what is different?
- You use X's and Y's with the capital and lower case letters.
- Examples:
- XBXb
- XBY
- *note: Y will never get a letter with it.
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Why do sex-linked traits typically affect more men than women?
Males have 1 X chromosome, which is where the sex-linked trait is located, and the Y chromosome is blank.
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When does independent assortment occur?
Metaphase I of meiosis
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During Anaphase II of meiosis, what separates?
SISTER chromatids
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What causes nondisjunction?
when a mitotic spindle breaks during cytokenesis.
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Phenotype
observable or physical trait
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Genotype
genetic code that explains phenotype
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Gene
unduplicated segment of a chromosome that codes for a trait
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Allele
alternate form of a trait or gene
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Homozygous
- 2 copies of the same allele
- Examples:
- YY or yy
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Heterozygous
- 1 copy of each allele
- Example:
- Yy
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Pleiotropy
one gene affects many phenotypes
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Polygenic inheritance
many genes affect 1 phenotype
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External thing that affects gene expression
Environment
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Chance of having a boy or girl?
50% for both
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Which is physically bigger: X or Y chromosome?
X
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X chromosome has _____ base pairs
Y chromosome has _____ base pairs
- X= 153 million
- Y= 50 million
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Colorblindness is ______ and on the ___ chromosome.
recessive; X
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