Transcript Genetics - Our Lady Of The Wayside School

• Passing of genetic material from parent to offspring
• Genetics
• Study of heredity
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Monk
Worked with pea plants
Father of Genetics
Studied traits
• Dominant
• Stronger trait
• Use capital letter (example tallness T)
• Recessive
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Weaker trait
Can disappear
Smaller letter (shortness t)
Every organism has 2 forms of the gene for each trait
True breeding: TT (tall plant) or tt (small plant)
• Genes- segments of DNA found in chromosomes for
characteristic
• Allele- different version of gene; get one version from each
parent
• Homozygous (purebred)- organism with 2 dominant or 2
recessive alleles
• Hertozygous (hybrid)- organism with one dominant and one
recessive allele
• Genotype- combination of alleles inherited by parents
• Phenotype- traits you can see
• Complete dominance- one trait is completely dominant over
another (you either have it or you do not)
Many genes can influence a single trait
• Skin, hair, and eye color are based on many alleles
A single trait can influence many traits
• Usually with genetic diseases
• Example: sickle cell anemia is on one gene
• Animals and their fur coats depend on living environment
• Humans can grow tall, but need proper nutrition
• Traits can also be learned: example being a good reader
(acquired)
• Incomplete dominance: no dominant or recessive
• Example:
P (parent generation) BB (brown)
WW (white)
F1 (first generation)
BW (palomino)
BW (palomino)
F2 (2nd generation)
BB (brown) BW (palomino) WW (white)
• Codominance: both genes contribute to the phenotype, have
both traits
• Example: 3 blood type alleles- A, B, O
• AB blood is co-dominant, get both A and B antigens
• One gene from each pair goes to each sex cell
Yy (parent)
Y (sex cell)
y (sex cell)
• Female: XX
• Male: XY
• Each gives one chromosome
• Male determines gender of child
• Each gene pair for a trait is inherited independently of the
gene pairs for all other traits
• Example: Tall plant
Tt
Yellow seeds
Yy