bio lab quiz 2
differentiation when turned on
turned on after determination turns it on - genes on control the structure and function of the cell and changes until it takes on its final form
heterozygous
two alleles are different
homozygous
two alleles at the locus are the same
What types of genes are typically activated during determination?
regulatory genes
t-test
told us if average measurements from two groups are different or not • null hypothesis- the difference between two means is zero
punnet square
top row: represents the gametes ( sperm) produced by the father Left column: represents the gametes (eggs) produced by the mother
What type of data is analyzed using a chi-squared ( χ2 ) test?
counts
What is cell determination?
molecular events leading to permanent cell differentiation
The allele for white hair in mice is autosomal recessive (b), while the allele for black hair is autosomal dominant (B). A white, female mouse mates with a black, male mouse. If the offspring are half black and half white, what are the possible genotypes for the black, male mouse?
Bb only
Hox genes
- Control embryonic development of body parts • Contribute to differentiation • Observed in fruit flies, mice, and humans
Blending inheritance two major problems
- not all characteristics show up as intermediate in offspring ( some resemble one parent and not the other or resemble a grandparent) - all variation in characteristics would be lost within a few generations (ex. hair color, population of humans have black hair and half have light brown hair. If they marry randomly with respect to hair color, in each generation there would be more people with dark brown hair and fewer with the original hair colors)
Meiosis
- occurs during the formation of gametes (eggs and sperm) - two round of cell division - end product: 4 daughter cells (haploid) - homologs become physically attached at meiosis I ( crossing over) then migrate to center of cell and remain physically paired - end of meiosis I: homologs separate
Pre-mendelian Ideas
- the observation that offspring resemble, but are not identical to their parents - offspring were a blend of their parents - ex. one parent had black hair and one had brown the kid would have dark brown hair
You have guinea pigs from two pure breeding lines. One line has black fur and red eyes and the other line has white fur and blue eyes. When you cross them, all the F1 guinea pigs have black fur and blue eyes. When you cross the F1s to one another, you get a total of 50 F2 offspring. There are 31 with black fur and red eyes, 15 with white fur and blue eyes, 2 with white fur and red eyes, and 2 with black fur and blue eyes. There are approximately equal numbers of males and females in each phenotypic category. If you were to do a χ2 test on the data, what would the expected value be for the individuals with white fur and blue eyes?
9.375
You have guinea pigs from two pure breeding lines. One line has black fur and red eyes and the other line has white fur and blue eyes. When you cross them, all the F1 guinea pigs have black fur and blue eyes. When you cross the F1s to one another, you get a total of 50 F2 offspring. There are 31 with black fur and red eyes, 15 with white fur and blue eyes, 2 with white fur and red eyes, and 2 with black fur and blue eyes. There are approximately equal numbers of males and females in each phenotypic category. What is the expected phenotypic ratio in the F2 assuming independent assortment?
9:3:3:1
Chi-square (x^2) test
A statistical method test that assesses the goodness of fit between observed values and those expected theoretically can reject or fail to reject a null hypothesis an tell us if our Punnett square models (expected phenotypes) and the data (observed phenotypes) are different or not
sex-linked
Dominant (female homozygous) Recessive (female homozygous) Recessive (female heterozygous)`
autosomal
Dominant (male homozygous) Dominant (male heterozygous) Recessive (female homozygous) Recessive (female heterozygous)
how are genes named
From the mutated phenotype after what happens in their absence
homologs
Members of a pair of chromosomes members of a homologous pair same size and same shape
What is cell differentiation?
The process in which cells become specialized.
where do multicellular organisms come from
a zygote: a single, fertilized egg cell
what are drosophila chromosomes made up of
X and Y chromosomes and three autosomes passed gene down by sex chromosome (x-chromosome)
What is the difference between an allele and a gene (locus)?
an allele is a particular version of a gene
genotype
any individual that has two alleles and that combination can be represented by the symbols for those alleles
discrete ordinal
ategories that have an order • Examples:Months(Jan,Feb, March), Small/Medium/Large
You have guinea pigs from two pure breeding lines. One line has black fur and red eyes and the other line has white fur and blue eyes. When you cross them, all the F1 guinea pigs have black fur and blue eyes. When you cross the F1s to one another, you get a total of 50 F2 offspring. There are 31 with black fur and red eyes, 15 with white fur and blue eyes, 2 with white fur and red eyes, and 2 with black fur and blue eyes. There are approximately equal numbers of males and females in each phenotypic category. Based on what you know, what kind of cross is being done here?
autosomal dihybrid cross
The allele for white hair in mice is autosomal recessive (b), while the allele for black hair is autosomal dominant (B). A white, female mouse mates with a black, male mouse. What are the possible genotypes for the white, female mouse?
bb only
You have guinea pigs from two pure breeding lines. One line has black fur and red eyes and the other line has white fur and blue eyes. When you cross them, all the F1 guinea pigs have black fur and blue eyes. When you cross the F1s to one another, you get a total of 50 F2 offspring. There are 31 with black fur and red eyes, 15 with white fur and blue eyes, 2 with white fur and red eyes, and 2 with black fur and blue eyes. There are approximately equal numbers of males and females in each phenotypic category. Which alleles are dominant?
black, blue
how are gene functions discovered
by examining the mutant phenotype
phenotype
characteristic of an organism ex. color, height, version of an enzyme, etc. expression of the trait in question
what does gene expression control
determination and differentiation
A cell in an embryo that still resembles the original cells of that embryo but will eventually form the spinal cord is ___.
determined only
degrees of freedom
df = n-1 number of categories minus one
categorical
distinct categories that have no order • Example: Types of horses (Palominos, Paints, Buckskins) We collected categorical data for our drosophila experiment We will use a chi squared test
Hox genes play an important role in _____________ development and contribute to ____________.
embryonic, differentiation
regulatory genes
expressed in determination - genes don't change the appearance of the cell but the expression of these genes control the expression of a series of other genes (cell fate)
definition of wildtype
fly has no mutation or is normal
pungent squares are useful genetic tools to allow us to __
generate hypotheses for inheritance patterns
X2 value
greater than any of the values on the row so we CAN reject the null hypothesis with a probability of p> 0.005 that the null is consistent with our data we CAN'T reject the null hypothesis when the p<0.005 (much less than)
Regeneration in limited powers
group of vertebrates called amniotes (mammals, birds, and reptiles) when lizards regenerate their tail they lack the various tissue types in the organ
ordinal data
have an order to them (can be discrete or continuous) We collected continuous data for our fiddler crabs • We will use a t-test
continuous ordinal
have order and are not categories • Example:Height,weight,etc.
homologous pairs
have the same loci but may or may not have the same alleles depending on whether the individual is homozygous or heterozygous at that locus loci are located on chromosomes
did the results support or refute knack and pomory
hypothesis was saying that the starfish are adapted so regeneration should be the same across the varying salt concentrations.
pharynx in planaria
in the middle of their bodies they have it and it serves as both a mouth and an anus
particulate inheritance
inheritance that occurs through units called genes. the genes pass from parents to offspring unchanged
Example case study involving ants and how they get back to their colonies
leg length was varied --> independent variable (cause) (under control of scientist) distance traveled is the dependent variable (effect)
locus
location of a gene on a chromosome
Girardia tigrina (formerly Dugesia tigrina) have an abundance of ________________ allowing them to regenerate body parts
neoblasts
pluripotent stem cells
neoblasts, that are undifferentiated cells with the ability to differentiate into specialized cell type
Mitosis
occurs when an organism is growing or when injuries are healing - during development - all chromosomes line up in the middle of the cell, attached to a series of microtubules ( spindle apparatus) - end result: two daughter cells ( genetically identical diploid cells)
what does the law of segregation state?
only one allele per locus is present in each gamete
law of segregation
parent passes one of its two alleles at a particular locus to each of its offspring punnet square indicates that variation is not lost through breeding but just may be hidden to reappear later
allele
particular version of a gene
dominant
phenotype expressed in heterozygote
recessive
phenotype not expressed in the heterozygote
regeneration in high powers
planarians Dugesia Tigrina ability to regrow an entire individual from any portion of the body
what would happen if a hox gene was mutated?
play a fundamental role in the development of the vertebrate central nervous system, axial skeleton, limbs, gut, urogenital tract and external genitalia, but can result in body parts and limbs in the wrong place along the body.
sister chromatids
prior to cell division each chromosome consists of two identical pieces
Mendel's first law of segregation can be represented using
pungent squares
expression
refers to the transcription of FNA and translation of mRNA to produce a functioning gene product
The production of a new structure, following the removal of an existing structure, in an adult animal is known as ___.
regeneration
Genetic Crosses
result in counts of offspring with different phenotypes so the X^2 test is a suitable method to determine how well the data fit mendelian expectations
fertilization
results in a diploid zygote gametes are haploid; thus it causes the union of two gametes to get the result
if more than one hypothesis was supported by the cross data, describe an experiment you could do or information you would need to determine the mode of inheritance
run the two specific crosses again and add it to the first experimental data then compare
genotype
set of genes found in an organism
Bilateral symmetry
single plane of symmetry splitting them into left and right sides that are mirror images of one another - planarians - animals have a head and CNS and other organ system formed during embryonic development
Assuming blending is the mode of inheritance, what would the offspring of a tall and short plant look like?
tall
Genes
the biological structures that are passed from parents to offspring and provide the information that gives each individual its own particular set of characteristics
null hypothesis
the difference between observed proportions of individuals of a certain phenotype and expected proportions is zero
What is development?
the process of change that occurs during an organism's life to produce a more complex organism
if a planarians head is cut down the middle...
the rest of the animal is not cut then each half of the head will regenerate the missing half resulting in a two-headed individual
hypothesis for kaack and pomory
the salinity levels in the Pensacola Bay influence arm regeneration.
Genetics
the study of the inheritance of characteristics from parent to offspring
Why is it important to use individuals from pure breeding lines to start crosses?
to ensure the individuals are homozygous
diploid
typical for animals and other eukaryotes cells have two copies of each gene. Ex. flower color in pea plants can be either purple or white. Color is influenced by the P locus, which has two alleles: P(purple) and p (white)
calculating chi square
x^ 2 = SUM (observed - expected)^2 / expected
Chi-square test
x^2 = sum of (O-E)^2/E test when your dependent variable consists of counts of individuals in different categories