Exam 2-HH

-Type A blood has __ antibodies in the plasma and type B has __ antibodies in the plasma -Type AB blood has ___ A or B antibodies -Type O blood has ___ A and B antibodies

B; A; neither; both

refers to severity or extent. Ex: Polydactyly is variably expressed. Ex: Polydactyly

Expressivity

maternal inheritance (mitochondrial genes), a form of vision loss, usually begins in teens or twenties, males affected more often. Blurring and clouding of vision usually the first symptoms. Vision loss results from the death of cells in the nerve that relays visual information from the eyes to the brain (the optic nerve)

Leber's hereditary optic neuropathy (LHON)

States that for 2 genes on different chromosomes, the inheritance of one gene does not influence the change of inheriting the other gene

Mendel's law of independent assortment

-the principle, originated by Gregor Mendel, stating that during the production of gametes the two copies of each hereditary factor segregate so that offspring acquire one factor from each parent. -Equal allele distribution into gametes and random combination gametes underlie this

Mendel's law of segregation

mutations in different genes that produce the same phenotype. Ex: Leber congenital amaurosis

Genetic Heterogeneity

A blood type called the Bombay phenotype also illustrates epistasis. It results from an interaction between a gene called __ and the __ gene that confers ABO blood type. The H gene controls the ___ of a molecule to which antigens A and B attach on red blood cell surfaces. In a person of genotype hh, that molecule isn't made, so the A and B antigens ___ attach to the red blood cell surface. The A and B antigens fall off, and the person tests as type ___ blood. However, he or she may be any ___ genotype.

H; I; placement; can't; O; ABO

-Blood type A=genotype ____ or ___ -Blood type B=genotype ___ or ___ -Blood type AB=genotype ___ -Blood type O=genotype ___

I^A I^A, I^A i I^B I^B; I^B i I^A I^B; ii

refers to the all-or-none expression of a genotype. Ex: Polydactyly

Penetrance

Environmentally caused traits that appears to be inherited; such a trait can either produce symptoms that resemble those of a known single-gene disorder or mimic inheritance patterns by affecting certain relatives. Ex: infection

Phenocopy

-Can not metabolize amino acid phenylalanine -Severe problems unless low-Phe diet -Affected by nutrition

Phenylketonuria - PKU

a single-gene disorder with many symptoms, or a gene that controls several functions or has more than one effect. ex: sickle cell anemia

Pleiotropic

-People who belong to to blood group A have an allele that encodes an enzyme that adds a final piece to a certain sugar to produce ___ ___ -In people with type B blood, the allele and its encoded enzyme are slightly different, which causes a different piece to attach to the sugar, producing antigen __ -People in blood group AB have ___ antigen types -Blood group O reflects yet a third allele of this gene. It is missing just one DNA ___, but this changes the encoded enzyme in a way that removes the ___ ___ from its final piece -Type O red blood cells lack both __ and __ -The A and B alleles are ___, and both are completely dominant to __

antigen A; B; both; nucleotide; sugar chain; A; B; codominant; O

different alleles that are both expressed in a heterozygote. Ex: ABO blood group

codominant

one allele is expressed, while the other isn't

complete dominance

The ___ (nutrition, exposure to toxins, previous illness, and gene modifieres) and ___ can also have an affect on phenotypic ratios

environment; temperature

Mendel's laws can appear not to operate when one gene masks or otherwise affects the phenotype of another. This phenomenon is called ___. It refers to interaction between ___ genes, not between the alleles of the same gene. EX: Bombay phenotype

epistasis; different

the heterozygous phenotype is intermediate between that of either homozygote. Ex: Familial hypercholesterolemia

incomplete dominance

A form of inheritance wherein the traits of the offspring are maternal in origin due to the expression of extranuclear DNA present in the ovum during fertilization.

maternally inherited traits

Mitochondrial cells are ___ inherited. They are passed only from an individual's mother because the sperm head, which enters an oocyte at fertilization, does not include ___, which instead are found in the sperm midsection, where they provide energy for movement of the tail. In the rare instances when mitochondria from sperm enter an oocyte, they are usually selectively ___ early in development

maternally; mitochondria; destroyed

The sequence of hundreds of DNA bases that makes up a gene can be altered in many ways, just as mistakes can occur anywhere in a written sentence. Different allele combinations can produce variations in the phenotype. The more alleles, the more variations of the phenotype are possible. This describes what? Ex: Cystic fibrosis

multiple alleles

Blood types are determined by the patterns of molecules on the ___ of red blood cells. Most of these molecules are proteins embedded in the plasma membrane with attached ___ that extend from the cell surface. The sugar is the ___, which is the molecule that the immune system recognizes

surfaces; sugars; antigen