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Genetics Notes
How do we inherit traits?
Heredity is defined as the passing of __traits__ from ___parent__ to ___offspring___. We
have __2__ genes for every trait (one came from your _mom__ and the other came from your
___dad___)
What traits can you inherit?
(Circle the traits that you can inherit.)
Eye color
Favorite food
Height
Your cloths
Favorite music
Having a tattoo
Hair color
Ear type
Can roll tongue
What are genes?
-Genes are segments of DNA that carry hereditary instructions
to code for traits. Genes are located on __chromosomes___.
- An allele is different forms of the same gene.
Alleles can be dominant or recessive.
Dominant trait: The trait observed when at least __one_
___dominant__ ___allele_ for a characteristic is ___inherited__. Represented by a
__capitol_ ___letter__.
Recessive trait: The trait that is apparent only when __two_ __recessive__ __alleles__ for
the same characteristic is __inherited___.
Phenotype vs. Genotype
The genotype is the genetic___ _make-up_ of an organism (in letters). The genotype is the
inherited combination of __alleles__.
The phenotype is an organism’s inherited ___physical__ __appearance__.
Homozygous vs. Heterozygous
Genotypes can be described as homozygous. Homozygous is When an organism has two alleles
that are the _same__. Another word for homozygous is ___purebred___
Ex: TT ; GG
;
dd
Genotypes can be heterozygous. When an organism has two alleles that are __different__.
Another word for heterozygous is ___hybrid___
Ex: Tt ; Gg
; Dd
Important Scientist in Genetics
1) Gregor Mendel is considered the father of genetics. He used pea
plants to study the way traits are passed from one generation to the
next. He was the first to discover how some traits are dominant over
others.
2) Reginald Punnett developed a square that is used to visualize all the
possible combinations of alleles in offspring resulting from a genetic
cross.