Chromosomal basis of inheritance Flashcards
(17 cards)
what is the chromosomal theory of inheritance
Mendelian genes have a specific loci on chromosomes and it is the chromosomes that undergo segregation and independent assortment
what are linked genes
genes located on the same chromosome
- tend to be inherited together
what is a sex-linked gene
the location of the gene on a sex chromosome
what does genetic recombination cause
offspring with new combinations of traits than parents
what are cytological maps
based on gene position relative to chromosomal features
does the egg or sperm carry the sex determinant in mammals
sperm
give some examples of sex-linked disorders in humans
- colour blindness
- duchenne muscular dystrophy
- haemophilia
what is aneuploidy
offspring with an abnormal chromosome number
what is trisomy
2n + 1
Trisomy 21 is Down syndrome
what is monosomy
2n - 1
in terms of alterations of chromosome structure, what is a deletion
removal of a chromosomal segment, can be final or it can lead to duplication, inversion and translocation
in terms of alterations of chromosome structure, what is a duplication
repeats a segment
in terms of alterations of chromosome structure, what is an inversion
reverses a segment within a chromosome
in terms of alterations of chromosome structure, what is a translocation
moves a segment from one chromosome to another non-homologous ones
which types of chromosomal alterations are often lethal
deletions, duplications, transloacyions
what is meant by maternal inheritance
the inheritance of mitochondrial DNA (mtDNA) ,, normally only inherited by the mother, therefore is non-Mendelian
what is genomic imprinting
certain traits in mammals depend on whether they inherited the allele from the male or female parent
Happens in gamete formation where one allele is silenced
e.g. in cats male wants kittens to grow big and fast, female wants it small when in womb
