Ch 16 BIO
Two babies are mixed up in the hospital nursery. The blood types of Couple 1 are A and O and the blood types of Couple 2 are AB and B. Baby Joe has blood type O and Baby Jane has blood type B. Who are the parents of Baby Joe and Baby Jane?
Couple 1, Baby Joe; Couple 2, Baby Jane
How can you determine the genotype of a plant showing the dominant phenotype of red color?
Cross the red plant with a white plant to see if any white plants appear.
Eyelash length is an inherited trait. In the human population, there is an eyelash length gene. There are two possible variants of this gene - an allele for long eyelashes (> 1cm) and an allele for short eyelashes (1 cm or less). How many eyelash length alleles does an individual have in one of her/his somatic cells?
2
An organism that is heterozygous for two traits can produce a maximum of _______ different gametes for these traits.
4
A couple has five sons. What is the probability that their next child will be a girl?
50%
A male is heterozygous for the trait that produces freckles on the skin, and he has freckles. If he marries a woman who is also heterozygous for freckles, ______ percent of their children will be freckled and __________ percent of their children will be heterozygous.
75%, 50%
What is a testcross?
A cross between an organism of unknown genotype with a homozygous recessive individual
Hemophilia is a sexlinked recessive condition that results in deficient blood clotting. The disease causes excessive bleeding which occurs spontaneously or upon slight injury. In dogs (as in humans) hemophilia is caused by a defect in a gene on the X chromosome. What will be the results of mating between a normal, noncarrier female dog and a male dog with hemophilia?
All of the offspring will be normal, but all females will be carriers.
Mendel's model organism for studying inheritance was the garden pea. What are the advantages of using peas to study genetics?
Garden peas are available in many varieties. Garden peas have a short generation time. Garden peas produce a large number of offspring with every mating. Mating between garden peas can be carefully planned and controlled
What is a dominant allele?
In a heterozygous individual, the allele that determines the phenotype
If a pink snapdragon is self-fertilized, the offspring are red, pink, or white. What type of inheritance pattern does flower color exhibit in this example?
incomplete dominance
Human males produce
sperm, half contain an X chromosome, half contain a Y chromosome
Color blindness is a recessive X-linked trait. A normal couple has a color-blind child. Who else in this family is probably color blind?
the child's maternal grandfather
Incomplete dominance is when
the phenotype of a heterozygote is not the same as either parent, but it is somewhere between the two parents.
In codominance,
the two alleles affect the phenotype in separate, distinguishable ways
In goats, the gene for coat color is on an autosome and light brown color is dominant to black. A light brown male is mated to a black female, producing a black kid (baby goat). If they produce another kid, could it be light brown? If so, what are the chances of it being light brown?
Yes, 50% as the male must be heterozygous for color
An X-linked gene is
a gene on the X chromosome.
The twofactor crosses performed by Mendel support the observation that
alleles for a given trait are distributed randomly among an individual's gametes independent of the alleles for other traits.
What features of meiosis allow for independent assortment of chromosomes?
Random alignment of homologous sister chromatids on the metaphase plate
