MolCell - Chapter 15 & 21

What does a frequency of recombination of 50% indicate?

The two genes are likely to be located on different chromosomes.

When Thomas Hunt Morgan crossed his red–eyed F1 generation flies to each other, the F2 generation included both red–and white–eyed flies. Remarkably, all the white–eyed flies were male. What was the explanation for this result?

The gene involved is on the X chromosome.

What is the reason that linked genes are inherited together?

They are located close together on the same chromosome.

SRY is best described in which of the following ways?

a gene region present on the Y chromosome that triggers male development

Red-green color blindness is a sex-linked recessive trait in humans. Two people with normal color vision have a color-blind son. What are the genotypes of the parents?

XRXr and XRY

Which of the following statements is true of linkage?

The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them.

How would one explain a testcross involving F1 dihybrid flies in which more parental–type offspring than recombinant–type offspring are produced?

The two genes are closely linked on the same chromosome.

Males are more often affected by sex–linked traits than females because

males carry only one X chromosome.

Thomas Hunt Morgan's choice of Drosophila melanogaster has been proven to be useful even today. Which of the following has/have continued to make it a most useful species?

1. its four pairs of chromosomes

2. few moral issues

3. easy and inexpensive maintenance

4. short generation time and large number of offspring

1, 2, 3, and 4

deletion

removes chromosomal segment

duplication

repeats chromosomal segment

inversion

reverses segment within chromosomes

translocation

moves segment from one chromosome to a nonhomologous. in reciprocal translocation nonhomologous chromosomes exchange fragments   

Date of when the process of meiosis was worked out.

1890s

Alleles of genes on nonhomologous chromosomes assort independently.

law of independent assortment

Date of when the process of mitosis was worked out.

1875

The two alleles for each gene separate.

law of segregation

Date of development of chromosome theory of inheritance.

1902

Why did white eyes only show up in Morgan's male fruit flies?

The allele for eye color was on the X chromosome.

A person with one X and one Y chromosome

male

A gene on the Y chromosome that is responsible for development of the testes.

SRY gene

The larger sex chromosome.

x chromosome

A person with two X chromosomes.

female

The smaller sex chromosome

Y chromosome

A gene that is located on either the X or Y chromosome

sex-linked gene

Genes located specifically on the X chromosome.

x-linked genes

Genes located specifically on the Y chromosome.

y-linked genes

Chromosome that also has genes for many characters unrelated to sex.

x chromosomes

Person that x-linked recessive disorders are much more common in.

male

Why does a tortoiseshell cat exhibit multiple colors?

X Inactivation

The name of the production of offspring that differ in from either parent.

genetic recombination

Offspring that have a phenotype that doesn't match either parent.

recombinants

Genes that are on the same chromosome and are usually inherited together.

linked genes

Offspring that have the phenotype of one of the parents.

parental type

Represents a 1% recombination frequency

map unit

A genetic map of recombination frequencies on a specific chromosome.

linkage map

A list of specific loci of genes on a particular chromosome.

genetic map

The probability of finding two genes separated from each other.

recombination

Frequency at which genes are on different chromosomes or far apart on the same chromosome.

50%

Study of how proteins work within a biological system.

systems of biology

Amount of genes within a genome

number of genes

Studying a large set of proteins and their functions.

proteomics

Stored known human genes in a silicon/glass "chip".

microarray

Number of base pairs in a genome

genome size

Amount of genes within a certain amount of base pairs

gene density

Genome size is not correlated with the number of genes in a genome.

true

Found as multiple copies in a genome.

repetitive DNA

DNA that can move from one location to another within a genome

transposable elements

Former genes that have accumulated mutations and are nonfunctional.

pseudogenes

DNA form of a transposable element.

transposons

RNA form of a transposable element.

retrotransposons

A series of repeating units of 2-5 nucleotides.

short tandem repeat

The increase of genome sizes over time has lead to _______ gene diversity.

morev

Duplication and inversions result in which of the following (hint: more than one answer)?

extra chromosomes, alterations of chromosomes structure

Unequal crossing over can result in:

deletions and duplications

how did Morgan study the fruit flies

mated red eye fruit flies with white eyed fruit flies

when morgan mated the flies, he found out that…

f1 generation had red eyes, f2 showed 3:1 red:white ratio

where is the SRY gene located?

y chromosome

the applications of computational methods to the storage and analysis of biological data

bioinformatics

study of whole sets of genes and their interactions

genomics

probability of recombination

centimorgan

the second X chromosome is condenses and deactivated

chromosomal inactivation

how does chromosomal inactivation affect females

the inactive X condenses into Barr Body

symptoms that a surviving individual of aneuploidy possesses

syndrome

what causes separate genes to be inherited together

recombination

genes that tell body parts where to develop

homeotic genes

what causes someone to have too many chromosomes

aneuploidy, polyploidy for plants

how are sex-linked traits inherited

through recessive alleles on the X chromosome

1 centimorgan equals

1% chance of crossing over

two examples of where we see multiple chromosomes come together form human chromosomes in the theory of evolution?

fusion and rearrangement

What causes variation/recombination in the sequence of base pairs in DNA?

duplication, deletion, inversion, translocation

what causes recombination between two genes

crossing over

what causes some genomes to be bigger than others

pseudogenes

what is the role of non-coding DNA?

determine if the gene is turned on or off

how does X inactivation affect males

it does not affect males because males only have one X chromosome

what did morgan find

specific genes were connected on certain chromosomes

morgans finds supported what theory

theory of inheritance

present multiple copies of a genome

repetitive DNA

What do various linkage percentages tell us?

recombination frequency

map unit

relative distance and order but not precises location of genes