94 lines
2.8 KiB
Markdown
94 lines
2.8 KiB
Markdown
[[G11 Pre-AP Biology]]
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Traits are genetic characteristics.
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Alleles are alternate forms of a gene.
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Genotypes are the genetic make up of an organism.
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Phenotypes are traits that get expresssed.
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Homozyhous are 2 identical alleles of a gene.
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Heterozygous are 2 different alleles of a gene.
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Gregor Mendel crossed 2 pea plants, of which were green and yellow, and expected the result to be greenish yellow. The resultings peas were yellow. He concluded that there is no blending effect.
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Gregor Mendel then crossed the yellows with the yellows, and the resulting was 6000 yellows and 2000 greens. The conclusion is that even if one train disappeared in F1 generation, it may reappear. Therefore there must bee 2 factors for each trait. These factors must segregate during meiosis.
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Dominance is a trait that always appears, example being brown hair.
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Recessive is a trait that only appears if both alleles of this trait is inherited.
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Mendel's laws:
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* Law of segregation: Each organism has 2 factors for each trait (2 alleles). During meiosis, each factor must separate.
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* Law of independent assortment: Inheritance of 1 trait foes not influence the inheritance of another.
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Punnet square, used to predict possible genotypes and phenotypic possibilities.
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Requires let statment, P, and gametes, tic tac toe board, genotypes and phenotypes.
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Example begin:
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Monohybrid cross:
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Must use uppercase for dominant and lowercase for recessive.
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Let statement:
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1 trait = abilitiy to taste.
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Let T rep better tasting allele.
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Let t rep no bitter tasting allele.
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P1 genotype:
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<u>TT</u> x <u>tt</u>
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homozygous taste cannot taste
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Gametes:
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F1 (filial I generation)
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![[Pasted image 20261019112113.png|391]]
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<u>Genotypes</u>:
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100% Tt
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<u>Phenotypes</u>:
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100% can taste bitterness.
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AFTER INCESTING TWO OF THESE
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$P_2$: Tt x Tt
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![[Pasted image 20261019112757.png]] <u>Genotypes</u>:
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25% TT
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50% Tt
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25% tt
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<u>Phenotypes</u>:
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75% can taste bitterness.
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25% can't taste bitterness.
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Example concluded.
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Autosomal traits are any traits found on chromosome 1-22.
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Carriers are people having a recessive allele.
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Sex linked traits are any traits found on sex chromosomes.
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X+Y are not homologous.
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X-linked means it's found on X chromosome.
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Y-linked means it's found on Y chromosome.
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Colorblindness is recessive and found on X chromosome.
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Hemophilia is the inability to clot blood and is found on the X chromosome.
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Hairy ears is a Y-linked.
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Example begin:
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Let:
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$X^h$= hemophilia allele
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$X^H$= no hemophilia
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$Y$= represents Y allele
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$P_1$:$X^HX^h$ x $X^HY$mop
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gametes: ($X^H$) ($X^h$) x -($X^h$) -($Y$)
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| | -($X^h$) | -($Y$) |
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| ------- | -------- | ------ |
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| ($X^H$) | $X^HX^H$ | $X^HY$ |
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| ($X^h$) | $X^HX^h$ | $X^hY$ |
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Genotypes:
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25% $X^HX^H$
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25% $X^HX^h$
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25% $X^HY$
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25% $X^hY$
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Phenotype:
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50% female + no hemophilia
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0% female + hemophilia
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25% male + no hemophilia
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25% male + hemophilia |