Classical Genetics Flashcards
Mendel’s Law of Segregation
Alleles are segregated or separated into different cells through the process of meiosis.
What type of dominance did Mendel study?
Simple dominance, exhibiting a trait from either one parent or the other
Explain incomplete dominance
The heterozygous gene(otype) exhibits an intermediate phenotype. Ex. cross between red and white flowers producing pink
Explain codominance
Both phenotypes show up, Ex. Cross between red and white flowers producing red/white spotted flowers instead of pink
Explain polygenic inheritance
When one phenotype is controlled by multiple genes being present and/or interacting with one another
How do traits “skip” a generation?
If a trait is caused by a recessive allele, only homozygous recessive kids will have the phenotype, all heterozygous kids will just be carriers. It may take few generations for a homozygous recessive child to be born.
What kind of trait shows up in every generation?
A trait caused by a Dominant allele.
What is a sex-linked disorder?
A gene that is present on one of the sex (X or Y) chromosomes.
Why are most sex linked disorders caused by the mother?
The male (Y) chromosome is very small, and usually only contains sex determining genes. The female (X) chromosome is much bigger and can hold extra and possible defective genes.
What are some sex linked disorders?
Hemophilia, Color-blindness,
How does a dominant disorder pass to future generations?
It doesn’t present itself until after the carriers reach reproductive age, this way they make more children before they realize they have it.
How do disorders that affect children get passed down?
They are recessive, and pass on through the heterozygous carriers, who are not afflicted but pass on the gene to their children.
What are autosomes?
The other 22 pairs of chromosomes that do NOT determine sex.
Why are males more likely to be color blind?
Colorblindness is a recessive trait on the x chromosome, the male only gets one of these alleles since he only has one X chromosome. If its recessive he will have color blindness. Whereas a female has the opportunity to get two alleles, if just one of her alleles is Dominant she will not have colorblindness.
What is a karyotype?
A picture of chromosomes during mitosis.
