I wonder what our kids would look like Genetics Review I wonder what our kids would look like

Heredity is passing traits from parents to offspring This happens through gametes (sperm and egg)

Most cells are diploid= cell contains two of each chromosome Gametes are haploid= cell contains one of each chromosome

Genes are located on chromosomes.

Only one of these chromosomes will go into this person’s gamete .

The gamete receives just one allele, not both. Use a Punnett square to learn what offspring genotypes could possibly result from crossing a male and female.

Monohybrid Cross - aka one trait What eye colors are possible for the children of a heterozygous brown eyed mom and a blue eyed dad? b b B b B b b b B b b b

Chickens can have different types of feathers Chickens can have different types of feathers. Frizzled feathers curl toward a chicken’s head. Assume that feather type is determined by a single gene and that the allele for frizzled feathers is dominant over the allele for straight feathers. In a cross between two chickens with straight feathers, what percentage of the offspring can be expected to have frizzled feathers? A) 0% B) 25% C) 50% D) 100%

In cocker spaniels the allele for a black coat color (B) is dominant over the allele for a brown coat color (b). If a brown cocker spaniel is crossed with a heterozygous black cocker spaniel, which of the following genotypic ratios can be expected? A) 0 BB: 2 Bb: 2 bb B) 1 BB: 2 Bb: 1 bb C) 2 BB: 0 Bb: 2 bb D) 2 BB: 1 Bb: 0 bb

Dihybrid Cross – two traits Tall T Short t Purple P White p Predict the F1 generation when you cross a homozygous tall homozygous purple- flowered plant with a heterozygous tall white plant. TTPP x Ttpp

T T P P x T t p p TP TP TP TP Tp Tp tp tp

TP TP TP TP Tp TTPp TTPp TTPp TTPp Tp TTPp TTPp TTPp TTPp tp TtPp TtPp TtPp TtPp tp TtPp TtPp TtPp TtPp

Phenotype: 100% Tall Purple Genotype: 50% TTPp & 50% TtPp Tall White (Ttpp) X Phenotype: 100% Tall Purple Genotype: 50% TTPp & 50% TtPp

The four butterflies in the illustrations represent the offspring in the F1 generation. Which statement is best supported by the phenotypes of these offspring? A) The F1 generation is composed only of males. B) Two of the offspring in the F1 generation will not be able to reproduce. C) The F1 generation is the result of a dihybrid cross. D) Two of the offspring in the F1 generation will experience a spontaneous mutation.

Facial dimples and free earlobes are both considered dominant human traits. What are the expected phenotypes of the offspring of a female with dimples and free earlobes (DDFf) and a male with no dimples and attached earlobes (ddff)? DF Df DF Df df DdFf Ddff DdFf Ddff A) 50% with dimples and free earlobes and 50% with dimples and attached earlobes B) 50% with dimples and free earlobes and 50% with no dimples and attached earlobes C) 75% with dimples and free earlobes and 25% with no dimples and attached earlobes D) 75% with dimples and attached earlobes and 25% with no dimples and free earlobes