Genetics Review

23 How many pairs of chromosomes do humans have?

Gregor Mendel Who is considered the father of genetics?

2 Brown: 2 Blue In huskies, brown eyes are dominant over blue. If a blue- eyed female mates with a heterozygous brown-eyed male, what will the phenotypic ratios of their offspring be?

Gene A _______ is a section of DNA that codes for a protein and determines a trait.

Phenotype The _________ is the physical characteristic of an organism.

1 Red: 2 Pink: 1 White In carnations, red and white petals are incomplete dominant. If a pink carnation is crossed with another pink carnation, what would be the phenotypic ratios of the resulting offspring?

Trait A ________ is a specific characteristic that varies from one individual to another.

Principle of Dominance “Some alleles are dominant and some are recessive” describes which of Mendel’s 3 Laws?

Incomplete Dominance ________ creates a blended phenotype; one allele is not completely dominant over the other.

X C X c vs. X c Y; males only get one option, and they can’t be carriers Why is it that a male child is more likely to inherit a sex-linked disorder, such as colorblindness than is his sister?

Heterozygous Has two different alleles for a particular trait; hybrid

Allele A(n) ________ is a form of a gene.

2 Dark Gray: 2 Speckled In Harbor Seals, light gray fur is Codominant to dark gray fur. If a female dark and light gray speckled seal mates with a male dark gray seal, what would be the phenotypic ratios of their resulting pups?

C. Four haploid daughter cells Unlike mitosis, meiosis results in the formation of A.Two haploid cells B.Four diploid daughter cells C.Four haploid daughter cells D.Two diploid cells

Multiple Alleles Three or more versions exist for a particular trait.

Recessive A ________ trait is one that will only appear in the phenotype if the organism inherits two of them

Principle of Segregation During gamete formation, alleles are separated from each other so that each gamete carries only a single copy of each gene. This describes which of Mendel’s 3 Laws?

True-Breeding Inherited two identical alleles for a given trait; homozygous or purebred

Sex-Linked Trait related to a gene that is found on the X or Y chromosome

Frankie Sally, an O blood type female and Chuck, an AB blood type male have 2 children together and have adopted a third child. The children’s blood types are as follows: Brad is A blood type, Karen is B blood type, and Frankie is O blood type. Which of the 3 children is adopted?

Independent Assortment Principle that genes do not influence each other’s inheritance because they are separated independently during meiosis

Codominance Both genes contribute to the phenotype of the organism, ex: spotted or striped

Gamete A ________ is a sex cell; sperm or egg.

1 unaffected female: 1 carrier female: 1 unaffected male: 1 male hemophiliac Hemophilia is a recessive sex- linked trait. If a female carrier for the disease marries an unaffected male, what will be the phenotypic ratios of their children?

Probability ________ is the likelihood an event will occur.

Hybrid A(n) ________ is an offspring of a cross between parents with different traits; heterozygous

Dominant Trait that will show up in an organism’s phenotype if present at all in the organism’s genotype

Yes Mark, a male with normal vision, and Allison, a female carrier for color-blindness, have recently had a son together. Assuming that color-blindness is recessive and sex-linked, is it possible that their son will be color-blind?

Genotype An organism’s ________ is its genetic makeup for a particular trait.

Homozygous Has two identical alleles for a particular trait; true-breeding or purebred

Punnett Square A _________ is a diagram that shows the possible results of a genetic cross

9 short-haired, bushy-tailed: 3 short-haired, flat- tailed: 3 long-haired, bushy-tailed: 1 long-haired, flat-tailed In squirrels, short hair is dominant over long hair, and bushy tails are dominant over flat ones. If 2 heterozygous short-haired and heterozygous bushy-tailed squirrels mate, what will be the phenotypic ratios of their resulting offspring? (Dihybrid)

Law of Independent Assortment Genes for different traits can segregate independently during the formation of gametes. This describes which of Mendel’s 3 Laws?

Segregation ________ is the separation of alleles during meiosis or gamete formation.

Polygenic A ________ trait is one controlled by two or more genes.

2 carrier females: 2 affected males Sickle-cell anemia is a recessive sex-linked disorder. If a female with the disease marries an unaffected male, what will be the phenotypic ratios of their children?

Pea Plants On what organisms did Gregor Mendel do his hereditary experiments?