AP Bio Genetics, Chi Square, Gene mapping, blood typing, Mendelian (and non Mendelian)

A baby has type A blood and the mother has type B, what should the father's blood type be?

Either AB or A

HOW TO FIND THE EXPECTED DECIMAL FOR THE CHI SQUARE

Ex 12 zodiac signs divided by 256 people = 21.333 Divide the amount of the kinds you have by the total number

X-inactivation

Female mammals inherit 2 X chromosomes ● one X becomes inactivated during embryonic development condenses into compact object = Barr body which X becomes Barr body is random patchwork trait = "mosaic"

Alleles

(Type) different alleles vary in the sequence of nucleotides at the specific locus of a gene some difference in sequence of A, T, C, G

In certain plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be short?

0

Monohybrid

1 characteristic. Flower color or seed shape

Which of the following are true for alleles

1) The can be identical or different for any given gene or somatic cell 2) They can be dominant or recessive 3) They can represent alternative forms of a gene

Steps to preform a chi square test

1) establish the research question 2) determine the null hypothesis 3) determine the alternate hypothesis 4) count observes values 5) determine expected values 6) calculate chi square value 7) calculate the degrees of freedom 8) select p value 9) identify critical value 10) compare the chi square value to critical value and draw conclusions

Co-dominance

2 alleles affect the phenotype equally & separately ● not blended phenotype ● human ABO blood groups ● 3 alleles AP Biology IA, IB, i IA & IB alleles are co-dominant glycoprotein antigens on RBC IAIB = both antigens are produced i allele recessive to both

For each characteristic, an organism inherits

2 alleles, 1 from each parent

Dihybrid

2 characteristics. Seed shape and seed color

PP x Pp ratio

3:1 - phenotype 1:2:1 - genotype

In the following human pedigree, squares represent males, circles represent females, and shaded symbols indicate individuals affected with a disorder. One of the affected males from the third generation has a child with a female who is a carrier. For the pedigree shown above, which of the following best expresses the probability that the couple's first son will be affected with the disorder?

50%

when crossing over a homozygous recessive with a heterozygote, what is the chance of getting an offspring with the homozygous recessive phenotype?

50%

what fraction of offspring from the cross AaBB x Aabb will be heterozygous for both traits?

8/16

What is the phenotypic ratio for a typical dihybrid cross

9:3:3:1

What is a karyotype?

A display of every pair of homologous chromosomes within a cell, organized according to size and shape

In many vertebrates, the sperm cell normally contributes which of the following to the new organism?

A haploid complement of chromosomes

Which of the following is the term for a human cell that contains 22 pairs of autosomes and an X and Y chromosome?

A male somatic cell

Mendel:

Bred pea plants ● cross-pollinate ● raised seed & then ● allowed offspring AP Biology true breeding parents (P) P = parental observed traits (F1) F = filial to self-pollinate & observed next generation (F2)

Test cross

Breed the dominant phenotype — the unknown genotype — with a homozygous recessive (pp) to determine the identity of the unknown allele

Sex linked traits

Genes are on sex chromosomes as opposed to autosomal chromosomes

Incomplete dominance

Heterozygote shows an intermediate, blended phenotype

Albinism

However albinism can be inherited as a single gene trait aa = albino

Jerry Springer is trying to determine who's the father. The mother has type A blood and the baby has type O blood. What could the genotype of the guy be for him to be the father

IBi

Rh factor

If present (+) if absent (-)

Genetics of Sex

In humans & other mammals, there are 2 sex chromosomes: X & Y 2 X chromosomes develop as a female: XX gene redundancy, like autosomal chromosomes an X & Y chromosome develop as a male: XY no redundancy

Which of the following best describes meiosis

It occurs only in cells in the reproductive structures of the organism

Lovus

Location

the pedigree below shows the inheritance of a dominant allele of a gene in a family over several generations. Circles represent females and squares represent males. Shaded symbols indicate the individual carrying the allele. The pedigree suggests that the gene is on a nuclear chromosome, and not on mitochondrial DNA because

Maternal mitochondrial mutations are inherited by all of the mother's offspring

Pleiotropy

Most genes are pleiotropic ● one gene affects more than one phenotypic character 1 gene affects more than 1 trait dwarfism (achondroplasia) gigantism (acromegaly)

Translocation

Occurs when the deleted chromosome fragment joins a nonhomologous chromosome.

Unlinked genes

On different chromosomes

Linked genes

On the same chromosome

Epistasis

One gene completely masks another gene ● coat color in mice = 2 separate genes B_C_ B_C_ bbC_ bbC_ _ _cc _ _cc C,c: pigment (C) or no pigment (c) B,b: more pigment (black=B) or less (brown=b) cc = albino, no matter B allele 9:3:3:1 becomes 9:3:4

Pedigree analysis

Pedigree analysis reveals Mendelian patterns in human inheritance ● data mapped on a family tree

If chi value is greater than critical value _____ if it is lesser _______

Reject; accept

Male pattern baldness

Sex influenced trait autosomal trait influenced by sex hormones age effect as well = onset after 30 years old dominant in males & recessive in females B_ = bald in males; bb = bald in females

Mother has type B, baby has Type A, if the father has type AB, which of the following statements is correct about the mother

She contribute an i allele, which is recessive to the fathers IA allele

Recessive diseases

The diseases are recessive because the allele codes for either a malfunctioning protein or no protein at all ● Heterozygotes (Aa)

Hemophilia is an X-linked recessive trait. If a man and woman have a son who is affected with hemophilia, which of the following is definitely true?

The mother carries an allele for hemophilia

In humans, red-green color blindness is a sex-linked recessive trait. If a man and a woman produce a color-blind son, which of the following must be true?

The mother carries the allele for color blindness

Degrees of freedom

The number of individual scores that can vary without changing the sample mean. Statistically written as 'N-1' where N represents the number of subjects.

Which of the following is the most likely explanation for a high rate of crossing over between two genes?

The two genes are far apart of the chromosome

Which of the following best describes the cell from the process of meiosis in mammals?

They are genetically different from their parents

If genes are close on the same chromosome

They will usually be inherited together and rarely crossover separately, they are linked

Types of blood

Type A - Only the A protein is present. Type B - Only the B protein is present. Type AB - Both proteins are present. Type O - Neither protein is present.

A woman who is a carrier of hemophilia marries a man who is not affected with hemophilia. What are the possible genotypes of their children?

XHXh, XHXH, XHY, XhY

Hemophilia is a recessive x-linked disorder. Which genotype represents a male with hemophilia

XhY

recessive allele

allele makes a malfunctioning protein

homologous chromosomes migrate to opposite poles during

anaphase 1

sister chromatids migrate to opposite poles during

anaphase 2

autosomes are

both present in every somatic cell of males and females alike

New combinations of linked genes are due to which of the following?

crossing over

which of the following statements about crossing over is incorrect

crossing over plays a role in both sexual and asexual reporduction

genotype

description of an organism's genetic makeup

phenotype

description of an organism's trait the "physical"

Heterozygous

different alleles = Pp

Law of independent assortment

different loci (genes) separate into gametes independently non-homologous chromosomes align independently classes of gametes produced in equal amounts YR = Yr = yR = yr only true for genes on separate chromosomes or on same chromosome but so far apart that crossing over happens frequently

Law or independent assortment

dihybrid (or more) cross 2 or more traits genes on separate chromosomes assort into gametes independently established by Metaphase 1 Exception: linked genes

which of the following can be diagnosed by examining a karyotype of an individual's white blood cells?

down syndrome

Law of segregation

during meiosis, alleles segregate homologous chromosomes separate ● each allele for a trait is packaged into a separate gamete

The process depicted in the image above is best summarized by which description?

during meiosis, crossing over leads to recombination of alleles between homologous chromosomes

Y chromosome

few genes other than SRY sex-determining region master regulator for maleness turns on genes for production of male hormones many effects = pleiotropy!

dominant allele

functional protein masks other alleles

gametes are

haploid

Carriers

have a normal phenotype because one "normal" allele produces enough of the required protein

Inversion

occurs when a chromosome fragment breaks off and reattaches to its original position but backwards!!! So now the part of the fragment originally at the attachment point is now at the end of the chromosome.

The Rule of Addition.

i. When calculating the probability that any of two or more mutually exclusive events will occur, you need to add together their individual probabilities. 1. If you are tossing a die, what is the probability that it will land on either the side with 4 spots or the side with 5 spots? a. 1/6 + 1/6 = 1/3

The Rule of Multiplication.

i. When calculating the probability that two or more independent events will occur together in a specific combination, multiply the probabilities of each of the two events. 1. The probability of a coin landing face up two times in two flips is ½ x ½=1/4 . 2. If you cross two organisms with the genotypes AABbCc and AaBbCc, the probability of an offspring having the genotype AaBbcc is ½ x ½ x ¼ = 1/16

three forms of the gene (alleles) that control the ABO blood group

iA, iB, and i. You have two alleles (one from your mother and one from your father), which are referred to as your genotype. The inheritance of the alleles is co-dominant, meaning that if the allele is present, it gets expressed

Genotype blood types

iAiA or iAi - Both genotypes produce the A protein (type A). • iBiB or iBi - Both genotypes produce the B protein (type B). • iAiB - This genotype produces the A and B protein (type AB). • ii - This genotype produces no protein (type O).

Diploid organism

inherits 2 sets of chromosomes, 1 from each parent homologous chromosomes like having 2 editions of encyclopedia

X-linked conditions are more common in men than in women because

men need to inherit only one copy of the recessive allele for the condition to be fully expressed

law of independent assortment refers to

metaphase 1 where homologous chromosomes can line up on either side of the metaphase plate

Law of segregation

monohybrid cross single trait each allele segregates into separate gametes established by Metaphase 1

The range of human skin colors is caused by a variety of genes, each of which has at least 2 alleles. This is an example of

multiple alleles

A person with turner syndrome has only 1 x chromosome. This means one of their gametes was missing a chromosome. Which of the following is why gametes sometimes lack a complete chromosome?

nondisjunction

Duplication

occurs when a chromosomal fragment broke off (causing the deletion above) becomes attached to its sister chromatid. o Zygote will get a double dose of the genes located on that chromosome.

Deletion

occurs when a chromosomal fragment is lost, o Results in chromosome with missing genes.

Nondisjunction

occurs when the members of a pair of homologous chromosomes do not separate properly during meiosis I, or sister chromatids dont separate properly during meiosis II. ⮚ One gamete receives two copies of the chromosome while the other gamete receives none.

X chromosome

other genes/traits beyond sex determination mutations: hemophilia AP Biology Duchenne muscular dystrophy

The physical appearance of an organism based on traits is

phenotype

genetic recombination

production of offspring with a new combination of genes inherited from the parents. ⮚ Many genetic crosses yield some offspring with the same phenotype as one of the parents (referred to as parental types) ⮚ Some offspring with phenotypes are different from either parent (referred to as recombinants).

Pleiotropy

property of a gene that causes it to have multiple phenotypic effects. o Sickle-cell disease has multiple symptoms all due to a single defective gene.

P= purple, pp = white. The offspring of a cross between two heterozygous purple-flowering plants (Pp x Pp) results in

purple-flowered plants and white-flowered plants

Homozygous

same alleles = PP, pp

Two plants are crossed, resulting in offspring with a 3:1 ratio for a particular trait. What does this suggest?

that the parents were both heterozygous

what is a genome

the complete complement of an organism's genes

A parent organism of unknown genotype is mated in a test cross. Half of the offspring have the same phenotype as the parent. What can be concluded from this result?

the parent is heterozygous for the trait

How do the two members of a pair of homologous chromosomes differ from each other?

the precise sequence of the DNA within each of the chromosomes

independent assortment of chromosomes is a result of

the random and independent way in which each pair of homologous chromosomes line up at the metaphase plate during meiosis 1

how would DNA in a horse muscle cell compare with the DNA in a horse sperm cell

the sperm cell would have half as much DNA as the muscle cell

A plant with purple flowers is allowed to self-pollinate. Generation after generation, it produces purple flowers. This is an example of

true breeding

Which of the following statements about genes is incorrect

under normal circumstances, each chromosome contains precisely 1 gene

Crossing Over:

⮚ Explains why some linked genes get separated during meiosis ⮚ During meiosis, unlinked genes follow independent assortment because they are located on different chromosomes. ⮚ Linked genes are located on the same chromosome and are not predicted to follow independent assortment. o HOWEVER, sometimes genetic crosses give results that seem to indicate some independent assortment has occurred, even when genes are on the same chromosome. ▪ These results are NOT due to independent assortment ▪ Research shows that the farther apart two genes are on a chromosome, the higher the probability that crossing over will occur between them. • The likelihood of crossing over between different genes on the same chromosome is expressed as a percent.