Lab 6 Flashcards
Sex chromosomes
A distinctive pair of chromosomes that are different in males and females; determine wether an individual is male or female
Autosomes
The non-sex chromosomes (in humans, there are 22 pairs)
Karyotype
Photographic representation of the chromosomes of an actively dividing cell, showing the number, shape and size of the chromosomes
Turner syndrome
One of two X chromosomes in a female genotype is missing
Phenotypic: short stature and non-functioning ovaries (infertility) are the most common features. A webbed neck and wide chest may also be present
1 in 2000 female births
Down syndrome
1 in 800
Cause by an extra autosomal chromosome #21 (trisomy 21)
Phenotypic: mild to moderate mental deficiency, almond shaped eyes, protruding tongue, and shorter limbs and neck
Klinefelter syndrome
1 in 500 births
Men have an extra X chromosome
Phenotypic: men are usually sterile testes and low levels of testosterone in their blood, some learning disabilities may be present
Sex linked gene
Gene found on a sex-chromosome; typically refers to genes found on the x but not the Y chromosome in humans
Pedigree chart
Diagram that shows the occurrence of phenotypic traits or genetic disease in successive generations, usually in humans; enable the analysis of how these traits are passed from parents to offspring
Carrier
Refers to an individual who has the recessive allele for a condition or disease but does not express any symptoms of the conditions of the disease. (Heterozygous for the trait)
Polygenetic inheritance
Phenotypic traits that involve contributions from alleles of several or many genes at multiple locations on the chromosome; typically with an additive effect
Histogram
Graphical display of data using bars of different heights
Recombinant DNA
DNA molecule carrying genes derived from two or more sources ( two species)
Non-parental genotype
Percent recombination
Total # of recombinants /total # of offspring X 100
Map units
Measuring genetic linkage
