T3L9 Linkage and Sex Linkage Flashcards
Does linkage increase or decrease genetic variation
Decrease
What is the position of a gene on a chromosome called
Loci/locus
What are two reasons that genes are inherited independently
- They are on separate chromosomes
- They are far apart on the same chromosome
Define linkage
The failure of two genes to assort independently OR the tendency of two or more genes to be inherited together
Will genes that are close together on the same chromosome be inherited together during meiosis
Yes
Why would genes that are close together on the same chromosome not be inherited together during meiosis
If they are split off during crossing over
The closer the gene, the _____ likely they are to be split up during crossing over
Less
Does crossing over or linkage increase genetic variation
Crossing over
What does it mean if a characteristic is sex-linked
The locus of the allele that codes for it is found on a sex chromosome
What are the chromosomes for male and female
XX for female and XY for male
Which chromosome is bigger X or Y
X
What is the difference between the genes on chromosome X vs chromosome Y
Chromosome X codes for female sex characteristics as well as some other characteristics whereas the Y chromosome only contains genes that code for male sex characteristics
Most genes carried on sex chromosomes are carried on which chromosome? What do we call this?
X chromosome so they are X-linked
What causes a recessive phenotype to occur
A lack of dominant alleles
Why are men more likely to present the recessive phenotype for sex-linked genes
Males will only have one copy of sex-linked genes found on their 1 X chromosome therefore they only need to inherit a recessive allele from one parent to have a lack of dominant alleles in their genotype and therefore present with the recessive phenotype