Genetics: Chapter 3 of Green book- cells and heredity<br />
GENETICS – The study of heredity. <br />Heredity – the passing of physical characteristics from parents to offspring. <br />Each characteristics is called a trait. <br />
What determines our traits?<br />Genes – the factors that control traits. <br />The different forms of genes are called alleles<br />An organism’s traits are controlled by the alleles in inherits from its parents. Some alleles are dominate, while others are recessive. <br />
Types of Traits: Dominate vs. Recessive<br />Dominate traits – a trait that always shows up when the dominate allele is present.<br />Recessive traits – a trait that is present only when no dominate allele are present. Sometimes it is present but hidden.<br />
How to represent dominate or recessive alleles. <br />Dominate traits are capitalized. <br />Ex. (Right handed = RH)<br />Recessive traits are not capitalized.<br />Ex. (Not right handed = rh)<br />
Mendel – The Father of Genetics.<br />Studied genetics by crossing pea plants. <br />Found out traits are not a blend of their parents’ characteristics. <br />
Different –otypes’<br />Phenotypes – organisms physical/visible traits.<br />Genotypes – organisms genetic make up. <br />Ex: Phenotypes could be – Brown eyes<br /> Genotype for that could be - BB<br />
Types of Genotypes<br />Homozygous – two identical alleles for a trait<br />(Brown eyes – BB)<br />Heterozygous – two different alleles for a trait<br />(Brown eyes – Bb)<br />Mendel called these hybrids<br />
Codominance<br />The alleles are neither recessive nor dominate, they both show up in an organisms offspring. <br />
PUNNETT SQUARES<br />Punnett square is a method for predicting the possible genotypes of offspring.<br />Write the examples down that I do on the board.<br />
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