Ch. 12. Notes: Genetics Mendel- The “Father of Genetics” -Used peas in experiments. -Peas are, in nature, self pollinators -Mendel was able to control.
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Notes: Genetics Mendel- The “Father of Genetics” -Used peas in experiments. -Peas are, in nature, self pollinators -Mendel was able to control the pollination by covering the flowers and removing the pollen grains.
Haploid= (Half)=(1N) *In Humans 1(23) = 23 *Half the normal number of chromosomes. *Find it only in gametes. Diploid=(Full set)=(2N) *In Humans 2(23) = 46 *Full number of chromosomes *Found in body cells
Genotype -The actual letters for a trait. Ex. BB, Hh, kk Phenotype -The physical appearance of a trait. Ex. Blue, Curly, Tall
Ex: Which is the genotype? A- White rabbit B- WW
Heterozygous -Hybrid -means “different”, use a Hh (one is capital, one is lower case) Homozygous -Purebred -means “same”, use HH or hh (Both are capital, or both are lower case.)
Allele -Used to describe the letters in a genotype. Ex. 2 alleles-BB There are 2 alleles for every trait, “one comes from mom and one comes from dad”.
Human Chromosomes Humans have 46 chromosomes, organized in 23 pairs.
The first 22 pairs are called AUTOSOMES. The last pair, #23, are called the SEX CHROMOSOMES. *In males it is XY and in females it is XX.
When female gametes form: XX Diploid ( beginning cell) X (egg)*** (3 polar bodies) *Haploid cells form and only give X’s to the offspring.
When male gametes form: XY Diploid (beginning cell) X Y Haploid *Haploid cells give either X or Y to the offspring.
Genes on the Sex Chromosomes The genes found on the sex chromosomes are called SEX- LINKED. Ex. Baldness in men
Usually with sex linked disorders, the males express/show the disorder and the females are the carriers.
Example: Colorblindness -Sex linked trait -Missing certain pigments in eyes to decipher certain colors. -Most common kind is red/green colorblindness -Affects 8% males and 1% females
Last, but not least… Dominant traits are written as ______ Capital letters, always written first if paired with a recessive allele. BB, Rr Recessive traits are written as ______ Lower case letters, always written second with the dominant allele. tt