Chapter 10.3 Flashcards
MONOHYBRID CROSS
a mating between individuals that are both heterozygous for the same gene
PUNNETTE square
uses the allele combination ( genotype ) of the parents to reveal which allele combinations the offspring may inherit
Homozygous recessive
are the only way to describe a receive gene that is expressed in a phenotype
what are the 2 possibilities of a dominant allele
Yy or YY ( homozygous dominant or heterozygous dominant)
TEST CROSS
is an experiment to help determine which dominant genotype a (YY or Yy) a offspring has
It is a mating between the two possibilities of unknown genotype (YY or Yy) with a homozygous recessive individual (yy)
to determine the unknown genotype.
( to determine the unknown genotype ( whether YY or Yy) of a plant it is crossed with a homologous recessive individual)
If the offspring are all the same their is 100% chance that the parent was a homologus dominant
If the offerings were divided (50%) in half there parent would heterozygous dominant Yy)
ALTERNATIVE VERSIONS
Medndel term for alleles
LAW OF SEGREGATION
although each parent gets a version of a gene , an allele, that may be different or the same, the homologs they reside on are separated in anaphase of meiosis I and pulled to opposite ends of the cell. So the homologous alleles of a gene are separated and are finally placed in different gametes
. Two alleles of each gene are packaged into separate gametes
.During meiosis , homologous pairs of chromosomes ( and the gene they carry) segregate from one another and a packaged into separate gametes.
At fertilization, gametes combine at random to form the next generation
following mendels law of segregation a plant genotype of Yy would produce gametes carrying
50 % Y( goes into one gamete) and 50 % y ( goes into the other)
following mendels law of segregation a plant genotype of YY would produce gametes carrying
Y in one gamete Y in the other
- What is a monohybrid cross, and what are the genotypic and phenotypic ratios expected in the offspring of the cross?
A monohybrid cross is a mating between two individuals that are both heterozygous for one gene. The genotypic ratio expected in a monohybrid cross is 1:2:1; the phenotypic ratio is 3:1.
How are Punnett squares helpful in following inheritance of single genes?
Punnett squares show the genotypes of each parent as well as the genotypes of potential offspring. Phenotypic and genotypic ratios of offspring can be predicted from the data in Punnett squares.
What is a test cross, and why is it useful?
A test cross is a mating between a homozygous recessive individual and an individual of unknown genotype. The genotype of the unknown parent can be deduced from the ratio of phenotypes in the F1 generation.
How does the law of segregation reflect the events of meiosis?
The law of segregation reflects the movement of homologous chromosomes into separate cells during meiosis I.
When heterozygous plants self fertilize, phenotype occurs in a distinct ratio
9:3:3:1
DIHYBRID CROSS
is a mating between individuals that are heterozygous for two genes
An individual with the genotype RrYy would produce approx equal numbers of of four types of gametes ( 4 phenotypes)
RY,ry,Ry and rY
dihybrd would have how many possibilities of offspring
16 with a phenotypic ratio of 9:3:3:1
THE LAW OF INDEPENDENT ASSORTMENT
based on dihybrid cross
. inference to metaphase in I in meiosis
. It states that during gamete formation, the segregation of alleles for one gene does not influence the alleles for another gene( provided that the genes are on sperate chromosomes
. alleles for two different gens are a re randomly packaged into gametes.
THE PRODUCT RULE
States that the chance that two independent events will occur = the product of the individual chances that each event will occur
. to calculate the offspring possibility for each gene from heterozygous parents e.g.. ( RrYy) set up Psquares for each (Rr xRr)
then Yy x Yy. calculate the ratio for whatever specific gamete you re looking for for each then multiply the answers of each gene together.
Or just find out for one offspring and raise it to number of offsprings
When does the law of independent assortment of snot apply
genes that close together on the same chromosome
What is a dihybrid cross, and what is the phenotypic ratio expected in the offspring of the cross?
In a dihybrid cross, two individuals that are heterozygous for two genes are mated. The phenotypic ratio that is expected is 9:3:3:1.
. How does the law of independent assortment reflect the events of meiosis?
The law of independent assortment reflects that each homologous pair of chromosomes aligns independently of other chromosome pairs during metaphase I of meiosi
How can the product rule be used to predict the results of crosses in which multiple genes are studied simultaneously?
The product rule allows you to estimate the odds that an offspring will have a certain combination of alleles for multiple genes by multiplying the probability that each separate event will occur.
