Project Flashcards
Define Chromosome
A combination of DNA with its associated proteins.
Define Karyotype
An image of the chromosome in a cell.
Define Homologous Chromosomes
The chromosomes present in a set. They have the same genes, but possibly different alleles. The number per set is called ploidy. They are the same size and structure, have the same genes, and you get 1 from each parent.
Mature gametes (sperm and egg cells) are _____.
Haploid
Define Autosome
Not the sex chromosomes, but they do contain sex determining genes.
Define Sex Chromosomes
Chromosomes that are involved in sex determination and segregate differently between the sexes. Many mammals have an XY sex determination where the XX is the female and the XY IS THE MALE.
Define SRY Gene
The SRY gene is the gene on the Y chromosome that acts as a master switch when it comes to turning on male development and suppressing female development. The female with XX lacks an SRY gene and develops as a female.
How is the creeping vole an exception when it comes to the SRY gene?
The X chromosomes do not have genes required for female development (SRY not required); those genes are distributed across the autosomes.
Define Chromatin
The DNA plus histones and other proteins that make up the chromosome.
Define Heterochromatin
When the chromatin is tightly wound up and condensed, it is called a heterochromatin.
Define Euchromatin
When the chromosome is relaxed, it is called euchromatin.
Gene expression takes place in the _____ and is generally suppressed in ______.
Euchromatin-Heterochromatin
The Y chromosome is mostly _____.
Heterochromatin
Do complete dominant and recessive alleles exist? What actually happens instead?
No, this is rarely the case; rather, both alleles are typically expressed from each autosome in equal amounts.
How does the balance of gene expression get messed with?
When errors in meiosis result in more than one homologous chromosome in a gamete, the balance of gene expression is off due to the increases in dosage.
What does the X-ist gene do in mammals?
It’s a gene on the X-chromosomes that codes for an RNA that is expressed on one of the two X’s.
Define Somatic Cells
All the cells except the germline cells (sex cells).
Define Germline Cells
The cells that will become gametes: ova or sperm. The other cells of the testis and ovaries required for gamete development are somatic cells.
What does the SRY gene typically do in mammals?
The expression of the Y chromosome gene, SRY, initiates testes development.
What are some important things to remember about mammalian Y chromosomes?
Have been evolving in males ONLY for millions of years.
Have lost most genes once shared with the X chromosome.
Have retained a core set of ancestral genes, some of which are found in all placental mammals.
It is thought that the surviving Y chromosome genes:
Retain the same functions as their homologs on the X chromosome
Are essential to the viability in XY individuals and are dosage-sensitive; expression from both copies is required for proper functioning.
What was expected from the genome of the creeping vole and what was actually discovered?
There was expected to be 8 Autosomes+ X+ Y= 10 different chromosomes.
There was actually 8 Autosomes+X=9 different chromosomes. (Absence of a Y CHROMOSOME)
What was found with the chromosomes present in male and female creeping voles?
Male Voles: XX
Female Voles: Only 1 X
What were some additional discoveries about the creeping vole genome?
The second sex chromosome in males has all the same genes as the large X that’s in both sexes.
The cellular machinery that usually silences gene expression from one X in XX individuals is activated in male creeping voles.
Both X chromosomes have all or most of the ancestral Y fused to one end.
Female creeping voles have 1 copy of all X chromosome genes + all the genes that gave survived for over a 100 million years on Y chromosomes.
What is the hypothesis generated for the project by the team?
Surviving Y chromosomes genes are essential to viability in individuals with 1X.
What is the general overview of procedures done in Lab for this project?
Will take vole tissue from various parts of the body; RNA will be isolated.
What is the purpose of the RLT Buffer in the procedure?
Its a lysis buffer for lysing cells and tissues before RNA or RNA/DNA isolation.
What happens to the RNA in spin column after it is done being centrifuged?
It is binding to the white part (portion at the bottom of the spin column).
What is the equation for Concentration?
C=Mass/Volume. (NG/ microliter)
What was being distributed to the strip tubes in the experiment?
You add 5 microliters of male to one, 5 microliters of female to another, and 2 microliters of loading dye to both.
What were the conditions for the gel electrophoresis?
1% Agarose gel was used and the voltage conditions were 130V for a duration of 30 mins.
