Studied by 1 person
Mendel’s heredity factors
Genes
The location of a particular gene can seen by…
Putting fluorescent dye on an isolated chromosome to highlight the gene
What are chromosomes made up of
Chromosomes are made up of histonproteins and DNA
The chromosome theory of inheritance
Mendelian genes have specific loci (positions) on chromosomes 2. Chromosomes undergo segregation and independent assortment (meiosis)
Law of segregation
2 alleles for each gene separate during gamete formation
Law of independent assortment
Alleles of genes on non homologous chromosomes assort independently during gamete formation
What did Morgan’s experiments with fruit flies prove
Thomas hunt Morgan’s experiments with fruit flies proved that chromosomes are the location of Mendel’s heritable factors
3 parts of the cell theory
Cells came from other cells 2. Cells are the basic unit of life 3. All living things are made of cells
Characteristics that make fruit flies a convenient organism for genetic studies
1) They breed at a high rate 2) a generation can be bred every 2 weeks 3) they only have 4 pairs of chromosomes (8 chromosomes)
Wild type
Most common or normal phenotypes
Mutant phenotype
Abnormal phenotypes
What did Morgan mate
Male flies with white eyes with female flies with red eyes
Thomas hunt Morgan’s results from his experiment with the flies
the F1 generation all had red eyes
The F2 generation had a 3:1 red:white ratio (Mendel’s ratio) but only males had white eyes
The white eyed mutant allele must be located on the X chromosomes
Morgan’s findings supported the chromosome theory of inheritance
What does it mean if there is a plus next to the phenotype variable?
it’s the wild type phenotype
What part of the Y chromosome are homologous with the X chromosome
Only the ends
SRY gene
The sry gene are on the Y chromosome and code for the development of testes
A sperm may contains either an…
X or a y
Who has more genetic information
females
do sex chromosomes only have genes related to sex?
No
Sex-linked gene
A gene located on either sex chromosome
What does sex linked usually mean for humans
A gene on the larger X chromosome
Disorders caused by recessive alleles on the X chromosomes
Color blindness, duchenne muscular dystrophy, hemophilia, and baldness
What does the inactivated X chromosome in the cell during embryonic development condense to?
Barr body
What is a Barr body similar to?
A co-dominant phenotype
Linked genes
Genes located on the same chromosome that tend to be inherited together because they are located near each other
Testcross
Crossing someone who is homozygous recessive with a heterozygous
Parental phenotypes
Observable traits inherited by offspring that relate to one or both of the parents traits. Genes usually inherited together in specific combinations
Genetic recombination
The production of offspring with combinations of traits differing from each parent
Offspring with nonparental phenotypes (new combinations of traits)
Recombinant types or recombinants
Crossing over
When you break the physical connection between genes on the same chromosome
The more farther apart genes are on a chromosome…
The more likely crossing over will happen
recombination frequency
Recombinants/total offspring
Recombination frequency
Tells you how likely a crossing over event will happen between two genes
