Chapter 6 - Complex Patterns Of Inheritance Flashcards
Codominance Definition
A situation in which both alleles are fully expressed. Equally expressed in a heterozygote: both alleys are dominant. (RW)
Incomplete dominance definition
A condition in which neither of the two alleles for the same gene can completely conceal the presence of the other. A heterozygous exhibits a phenotype that is somewhere between a dominant phenotype and a recessive phenotype.
Multiple Alleles Definition
A gene with more than two alleles.
Multiple Alleles Rabbit Coat Colour
The gene that controls coat colour in rabbits has four alleles : agouti (C), chinchilla (c ch) , Himalayan (c h ) and albino (c)
Multiple Alleles Blood Type
Different combinations of the three I alleles result in four different blood types: type A, type AB, type B, type O
Multiple Alleles Clover Leaf
A single gene is responsible for clover leaf pattern, thee are seven different alleles for the pattern. Varying combination of these result in 22 different patterns that can be expressed in clover leaves.
V v 1 v h v f v ba v b v by
Sickle Cell Anemia definition
One of the most thoroughly studied genetic disorders. Often described as being the result of autosomal recessive
Heterozygous Advantage definition
A survival benefit for individuals who inherit two different alleles for the same trait.
Environmental Effects
Environmental conditions often affect the expression of traits. For example, some genes are influenced by temperature.
Polygenic Inheritance
Continuous variation definition
A range of variation in one trait resulting from the activity of many genes.
Polygons definition
A group of genes that all contribute to the same trait. Each dominant allele contributes to the trait. Recessive alleles do not contribute to the trait. Ex. Skin
Mendel’s experiments definition (complete dominance)
Traits studied were either dominant or recessive
One dominant allele was enough to produce dominant phenotype.
Incomplete Dominance definition
Method of inheritance where by the heterozygous condition produces an intermediate form between the dominant and recessive characteristics.
Linked genes definition
Genes that are the same chromosome and that tend to be inherited together.
Sex linked genes definition
A trait controlled by genes on the X or Y chromosome.
Sex linked genes Examples
XX females XY males for mammals
XY females XX males birds,moths, and butterflies
Sex Linked Holandric genes
Genes found on the non-homologous Y chromosome.
Who discovered fruit flies have different eye colours and the traits
Morgan.
XRXR, XRXr, XrXr, XRY, XrY
Sex Linked Traits
Red-green colour vision deficiency (CVD)
Cannot distinguish between certain shades of red and green. X linked recessive.
Sex Linked Traits
Duchenne Muscular Dystrophy
Progressive weakening of muscles and loss of coordination. X Linked recessive
Sex Linked Trait
Hemophilia definition
Cannot produce a necessary blood clotting factor. X Linked recessive
Sex Linked Trait
Adrenoleukodystrophy Definition
A build-up of fatty acids that causes progressive brain damage and death . X linked recessive
Sex Linked Trait
X Linked severe combined immunodeficiency (SCID)
Decreased immune response due to low white blood cell count. X Linked Recessive
Sex Linked Trait
X Linked hypophosphatemia definition
Softening of bone, which leads to bone deformity. X Linked Dominant
Sex Linked Trait
Hairy Ears definition
Hair grows on the outside of the ears. Y Linked
Barr Body definition
In every female cell, one of the X chromosome is inactive. The inactive X chromosome is condensed tightly into a structure known as a Barr body. And affects the gender.
Human Genome Project definition
Determines the DNA sequences of other organisms. Allows scientists to make comparisons between species and learn even more about important features of genomes.
What is Our Genome?
Only about 2 percent of the nucleotides in the human genome make up our genes and code for all the proteins in the body.
The estimated 25,000 total number of genes is much less than scientists predicted. Previous estimates were between 80,000 and 140,000.
Over 50 percent of our DNA consists of streches of repeating sequences.
There is very little genetic variation within our species. About 99.9 percent of the DNA sequence is almost exactly the same in all people.
