Dominant Trait in Humans A blood type Abundant
Dominant Trait in Humans A blood type Abundant body hair Astigmatism B blood type Baldness (in male) Broad lips Broad nose Dwarfism Hazel or green eyes High blood pressure Large eyes Migraine Mongolian Fold Nearsightedness Rh factor (+) Second toe longest Short stature Six fingers Webbed fingers Tone deafness White hair streak Recessive Trait in Humans O blood type Little body hair Normal vision O blood type Not bald Thin lips Narrow nose Normal growth Blue or gray eyes Normal blood pressure Small eyes Normal No fold in eyes Normal vision No factor (Rh -) First or big toe longest Tall stature Five fingers normal Normal fingers Normal tone hearing Normal hair coloring
GENETICS VOCABULARY Homozygous- an organism that has two copies of the same allele for a gene ▪ Both can be dominant (AA) ▪ or Both can be recessive (aa) Heterozygous- an organism that has two different alleles for a gene. ▪ One dominant, one recessive (Aa)
GENETICS VOCABULARY Genotype- describes the alleles that an organism has (the type of genes it has). ▪ Homozygous Dominant (AA) is an example of a genotype
GENETICS VOCABULARY Phenotype- describes the actual trait that an organism has. ▪ Genotype controls Phenotype ▪ Having blue eyes is a phenotype, Meghan’s genes caused his eyes to have this phenotype
PUNNETT SQUARES Punnett Squares are used to determine the probability of genes and traits in an organism. A A a a
PUNNETT SQUARES Punnett Square use the parental genes. ▪ If we cross two “Aa” parents, we would start with this square: A a A AA Aa aa
PUNNETT SQUARES Step 6: Determine the traits of the offspring: AA= _____ trait A a Aa= _____ trait aa= _____ trait A AA Aa aa
Journ. AL PROMPT: Dec 15, 2016 In summer squash, white fruit is dominant. Yellow fruit is recessive. A squash plant that is homozygous dominant is is crossed with a yellow fruit. Using a Punnett Square, predict the phenotypes of the offspring of these plants:
Extra • Coat color in guinea pigs can be black or white. Matings between black guinea pigs sometimes yield 3 black : 1 white and sometimes yield all black offspring. Crosses of black x white sometimes produce all black progeny and sometimes produce a ratio of 1 black : 1 white. White x white crosses produce only white offspring. Explain these results, and indicate which trait is dominant. Write the genotypes of the parents and the offspring for all three crosses mentioned.
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