Mendelian Concepts - Ch: 12 Flashcards
Allele
Versions of gene that express different protein resulting in different traits
What’s genotype
Type of genes a person has; For example: Blood alleles are A, B, and O. Every person can carry two; one from mom and one from dad.
What’s homozygous, heterozygous, or hemizygous?
homozygous: same alleles
heterozygous: different alleles
hemizygous: only one allele (maybe because gene is lost)
What are the female and male genes?
Female: X, X
Male: X, Y
What’s codominance?
When both alleles are expressed
What’s the dominant blood type?
AB where both proteins are expressed. Reference: AO means A while BO means B
What’s incomplete dominance?
Blending of two alleles together to express a characteristic (Phenotype) that they would have not by themselves
Example of incomplete dominance?
Child having wavy hair while one parent has curly and one has straight hair
What’s phenotype?
A characteristic caused by an expression of gene is called phenotype
Penetrance?
A gene can express itself yet not express the characteristic. Penetrance is rate at which a trait is expressed
Best explanation for penetrance:
100 people may have a gene that can express breast cancer while only 60 of them get it meaning the gene is 60% penetrant
What’s expressivity?
To a degree that gene is expressed. For example: a gene causing disorder maybe expressed to more degree where it has worst symptoms
What’s a mutation?
Change in gene that may or may not cause a change in characteristic.
Eg. Frameshift mutations change the DNA sequence due to deletion or insertion of nucleotides.
What do chromosomal mutations do?
They are involved in completed deletions, duplications, inversions, insertions or translocation of larger segments of DNA.
What’s law of segregation?
When a parent randomly passes it’s allele to the offspring and gamete is formed which carry one allele for any inherited trait
Law of independent Assortment
Explains that inheritance of one gene cannot affect the inheritance of another gene. For example, a kangaroo can have grey color from but short tail from dad.
What are diploid cells?
Cells that have complete set of chromosomes. Humans have 46 chromosomes. Diploid cells (2n) undergo meiosis that form gamete with half number of chromosome i.e. haploid cells (n),
What’s interphase?
A cell goes through two major events; interphase during which cell grows and meiosis or mitosis for division
What’s meiosis (reductional division) like?
It’s same steps as mitosis, however, it is carried out twice; I and II, so it produces four daughter cells instead of two like mitosis
What’s unique to meiosis?
Synapsis where two chromosomes (tetrad) are joined together to allow gene recombination and crossing over through a protein called synaptonemal complex
