Chapter 15 - Genetics and inheritance Flashcards
Allele
Alternate forms of a gene that occur at a given point in a chromosome
Co-dominance
when two different alleles both show up in the phenotype (immunoglobin A and B in blood groups)
recessive sex linked inheritance
Red-Green colour blindness, Hemophilia, Duchenne type of muscular dystrophy
Recessive autosomal inheritance examples
Cystic fibrosis, phenylketonuria (doesnt have enzyme to convert phenylalanine)
Dominant autosomal inheritance examples
Achondroplasia (dwarfism), huntingtons diease
DNA profile
pattern of bands from a persons DNA that is revealed from electrophoresis
genome
complete set of genetic information of an organism
hemizygous
having no allele counterpart, occurs with alleles in the X chromosome in males as they dont have an allele counterpart on the Y chromosome.
marker
segment of DNA with known characteristics, can be used to compare DNA profiles
pedigree
family tree
in terms of inheritance patterns. Genes
come in pairs, one from each parent
phenotype
physical appearance of an individual from the expression of alleles for that gene
severe genetic defects are rarely passed on to the next generation
often results in life threatening conditions that means die before reproductive age or cause severe diability so are too disabled to reproduce
huntingtons disease
symptoms of difficulty in voluntary movements and cognitive decline start at age 40 and gets worse
phenylketonuria
condition where body doesnt have the enzyme to convert phenylalanine amino acid into tyrosine, builds up to toxic levels in the body, causing mental retardation and seizures
sex linked characteristics
determined by the genes carried on the X chromosome.
duchenne type of muscular distrophy
X linked recessive disorder that leads to progressive muscle weakness
patterns in sex linked inheritance
- mother is homozygous recessive then son will have the condition
- daughter has trait then father also has the condition
DNA profiling
analysis of specific regions of a persons DNA to distinguish people from one another
electrophoresis
technique used to reveal DNA profiles in a banded pattern
1. treat DNA sample with restriction enzyme to make staggard cuts when it comes across a specific base sequence
2. elecrophoresis where DNA fragments are separated on their size - DNA is negatively charged as of phosphate group in the backbone so smaller DNA peices move faster.
3. results in a pattern of bands called a DNA profile
DNA profile
pattern of bands revealed by the process of electrophoresis
DNA profile in identifying hereditary diseases
presence of alleles that can increase individuals chance of inheriting certain cancers or can cause hereditary diseases like cystic fibrosis or huntingtons disease
DNA profile is used to trace ancestory
compare DNA profiles to see common alleles present as parents will pass alleles on to their children so will have some of the same bands
marker
DNA segment of a sequence of bases with known characteristics, used for comparison in genetic testing
DNA profile for forensics
individuals DNA should have identical DNA to the sample for it to match
DNA profiling can determine risk of having a child with genetic disorder
detect if parents are carriers of specific genes associated with disorders or if genetic conditions are present in the fetus