Genetics (Younger) Flashcards
Basic unit of inheritence
Gene
The physical location of a gene on a chromosome
Locus
Alternative forms of a gene at a given locus
Allele
genetic constitution of an individual
Genotype
Observed expression of a gene (physical manifestations) genotype plays a role (environment and other genes also play a role)
Phenotype
You have 2 alleles at a single locus and they are identical
Homozygous
You have 2 different alleles at a single locus
Heterozygous
A condition seen in both the homozygote and the heterozygote; only one copy of the mutant allele is necessary for phenotypic expression.
Dominant
A condition seen only in homozygote; requires two copies of the mutant allele for phenotypic expression.
Recessive
A nonsex chromosome (humans have 22)
Autosomes
X or Y chromosome
Sex chromosome
2 copies of each chromosome
Diploid
one copy of each chromosome
Haploid
All cells in the body except gametes (these are always diploid)
Somatic cells
Sperm or egg cells (always haploid)
Gametes
Produced by the effect of a single gene (or gene pair) usually transmitted in simple patterns as autosomal dominant, autosomal recessive, or X-linked
Single gene disorders
deviation from the normal chromosome number or structure
Chromosome abnormalities
Combined effects of multiple genetic and non-genetic influences
Multifactorial traits
A disease or condition that is present at birth, (can be either hereditary or acquired)
Congenital
What percentage of the population will suffer from a disorder with a genetic component during their lifetime
60%
Autosomal dominant disorders often involve catalytic or non-catalytic?
Most of the time, autosomal dominant disorders caused by potentially one allele, are involved with non-catalytic proteins.
How many mutant alleles are needed for the disease to be expressed with autosomal dominant disorder?
Only one mutant allele needed
Look at pedigree on slide 9…From this pedigree what is the genotype of the mother? Does the dad have a mutant allele?
She has just one mutant allele, because some of her kids don’t have the disease
No father does not have mutant allele
Look at pedigree on slide 9…From this pedigree what is the genotype of the mother? Does the dad have a mutant allele?
She has just one mutant allele, because some of her kids don’t have the disease
No father does not have mutant allele
What are some diseases that are considered autosomal dominant disease?
Familial hypercholesterolemia (LDL receptor deficiency) Huntington disease (tri-nucleotide repeats) Myotonic dystrophy (muscular atrophy and wasting) Neurofibromatosis type 1 (nerve tissue tumor) Osteogenesis imperfecta (collagen mutation) Marfan syndrome (connective tissue defect)
