BIOL 3301 Exam 1 Overview and Key Questions

chi-square test null hypothesis

The genes are assorting independently.

crossing over likelihood

between genes that are far apart

The physical, proteinaceous structure that is formed during synapsis is called a synaptonemal complex

The physical, proteinaceous structure that is formed during synapsis is called a synaptonemal complex.

The genetic composition of an individual

genotype

Chromosomal deletions and duplications

abnormal crossover events.

pea plant genotypes

Rr × rr.

Type O blood = type A with type B blood.

impossible blood type

an organized representation of the chromosomes within a cell.

karyotype

Two genes that are located on the same chromosome are said to be

physically linked genes

states that two different genes will randomly assort their alleles during the formation of haploid cells.

Law of Independent Assortment

expected phenotypic ratios

616 short/white flower, 1850 tall/white flower, 1850 short/purple flower

In a dihybrid cross of two heterozygous individuals

9:3:3:1 phenotypic ratio

.haploinsufficiency explanation

a single functional copy of the gene produces insufficient gene product for normal biological function.

A stage in cell division where chromosomes are aligned in the center of the cell.

Metaphase

The stage of mitosis where the nuclear envelope breaks down and spindle fibers attach to chromosomes.

Prometaphase

The first stage of cell division where chromosomes condense and the mitotic spindle begins to form.

Prophase

The stage of cell division where sister chromatids are pulled apart to opposite sides of the cell.

Anaphase

The final stage of cell division where chromosomes de-condense and the nuclear envelope re-forms.

Telophase

A gamete from a diploid organism with 14 pairs of chromosomes will have

7 chromatids

possesses a phenotype that is intermediate between the homozygous dominant and homozygous recessive phenotypes.

A heterozygote possesses

From diploid cells that are heterozygous for both tall and leaf color alleles, you expect an equal number of Tp, tP, tp, and TP gametes.

Tp, tP, tp, and TP gametes.

Recombination occurs

prophase of meiosis I.

The production of wild-type offspring from a cross between parents that both display the same recessive phenotype illustrates the genetic phenomenon of complementation.

Wild-Type Offspring

The probability that an offspring will have an ssRR genotype from a cross of two SsRr individuals is 6.25%.

Probability of ssRR Genotype

A testcross is always performed between the individual that is heterozygous for the genes to be mapped and an individual who is homozygous recessive for the genes.

Testcross Definition

The most likely mode of transmission for a very rare trait in the population could be autosomal dominant.

Mode of Trait Transmission

An individual carries the allele for polydactyly, a dominant trait, but is phenotypically normal, which is an example of incomplete penetrance.

Incomplete Penetrance

Isolating a new mutation in an allele of a gene that alters the phenotype observed from a mutant of a separate gene is an example of modifier interaction.

Gene Interaction Type

In a mapping experiment with three linked genes, the phenotype that should occur least often in the F2 offspring is the phenotypes of individuals with double crossover events.

Least Common Phenotype in Mapping

The genotypes of the parent flies in a cross resulting in 40 red-eyed males, 80 red-eyed females, and 40 white-eyed males are Xw+Y and Xw+Xw.

Parent Genotypes in Fruit Flies